CHROMIUM: add boot-to-device mapper support.

Documentation/kernel-parameters.txt

                           Kernel Parameters
                           ~~~~~~~~~~~~~~~~~
 
 The following is a consolidated list of the kernel parameters as implemented
 (mostly) by the __setup() macro and sorted into English Dictionary order
 (defined as ignoring all punctuation and sorting digits before letters in a
 case insensitive manner), and with descriptions where known.
 
 Module parameters for loadable modules are specified only as the
 parameter name with optional '=' and value as appropriate, such as:
@@ skipping 25 matching lines @@
 parameter is applicable:
 
         ACPI    ACPI support is enabled.
         AGP     AGP (Accelerated Graphics Port) is enabled.
         ALSA    ALSA sound support is enabled.
         APIC    APIC support is enabled.
         APM     Advanced Power Management support is enabled.
         AVR32   AVR32 architecture is enabled.
         AX25    Appropriate AX.25 support is enabled.
         BLACKFIN Blackfin architecture is enabled.
+        DM      Device mapper support is enabled.
         DRM     Direct Rendering Management support is enabled.
         EDD     BIOS Enhanced Disk Drive Services (EDD) is enabled
         EFI     EFI Partitioning (GPT) is enabled
         EIDE    EIDE/ATAPI support is enabled.
         FB      The frame buffer device is enabled.
         GCOV    GCOV profiling is enabled.
         HW      Appropriate hardware is enabled.
         IA-64   IA-64 architecture is enabled.
         IMA     Integrity measurement architecture is enabled.
         IOSCHED More than one I/O scheduler is enabled.
@@ skipping 570 matching lines @@
         disable_mtrr_trim [X86, Intel and AMD only]
                         By default the kernel will trim any uncacheable
                         memory out of your available memory pool based on
                         MTRR settings.  This parameter disables that behavior,
                         possibly causing your machine to run very slowly.
 
         disable_timer_pin_1 [X86]
                         Disable PIN 1 of APIC timer
                         Can be useful to work around chipset bugs.
 
+        dm=             [DM] Allows early creation of a device-mapper device.
+                        See Documentation/device-mapper/boot.txt.
+
         dmasound=       [HW,OSS] Sound subsystem buffers
 
         dma_debug=off   If the kernel is compiled with DMA_API_DEBUG support,
                         this option disables the debugging code at boot.
 
         dma_debug_entries=<number>
                         This option allows to tune the number of preallocated
                         entries for DMA-API debugging code. One entry is
                         required per DMA-API allocation. Use this if the
                         DMA-API debugging code disables itself because the
@@ skipping 2107 matching lines @@
         xirc2ps_cs=     [NET,PCMCIA]
                         Format:
                         <irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
 
 ______________________________________________________________________
 
 TODO:
 
         Add documentation for ALSA options.
         Add more DRM drivers.