Add nvflash config file for SPI

overlay-variant-tegra2-seaboard/burn-u-boot/flash-spi.cfg

Index: overlay-variant-tegra2-seaboard/burn-u-boot/flash-spi.cfg
diff --git a/overlay-variant-tegra2-seaboard/burn-u-boot/flash-spi.cfg b/overlay-variant-tegra2-seaboard/burn-u-boot/flash-spi.cfg
new file mode 100644
index 0000000000000000000000000000000000000000..e1503a02424eb0c7922fa912c8cfba78138346fa
--- /dev/null
+++ b/overlay-variant-tegra2-seaboard/burn-u-boot/flash-spi.cfg
@@ -0,0 +1,40 @@
+[device]
+type=spi
+instance=0
+
+[partition]
+name=BCT
+id=2
+type=boot_config_table
+allocation_policy=sequential
+filesystem_type=basic
+size=204800
+file_system_attribute=0
+partition_attribute=0
+allocation_attribute=8
+percent_reserved=0
+
+[partition]
+name=PT
+id=3
+type=partition_table
+allocation_policy=sequential
+filesystem_type=basic
+size=65536
+file_system_attribute=0
+partition_attribute=0
+allocation_attribute=8
+percent_reserved=0
+
+[partition]
+name=EBT
+id=4
+type=bootloader
+allocation_policy=sequential
+filesystem_type=basic
+size=1826816
+file_system_attribute=0
+partition_attribute=0
+allocation_attribute=8
+percent_reserved=0
+filename=/build/tegra2_seaboard/u-boot/u-boot.bin