Fix pread64, pwrite64, readahead for ARM.

Fix pread64, pwrite64, readahead for ARM.

The system calls taking a 64-bit argument have a special quirk on ARM.
The 64-bit argument is passed in a pair of two registers that must be
an even/odd pair.  If it's an odd-numbered argument, then there is a
dummy argument first that is ignored to consume the odd-numbered argument
register before the even/odd pair.

BUG= none
TEST= sys_pread64 now works correctly on ARM

R=markus@chromium.org
Committed: http://code.google.com/p/linux-syscall-support/source/detail?r=9

[Markus (顧孟勤), 2011-11-21 22:00:56]

lgtm