tegra124: Add the tegra124 compatibility string to crossystem.
tegra124: Add the tegra124 compatibility string to crossystem.

Teach crossystem the tegra124 compatibility string so that it can identify the
platform for tegra124 based systems.

I called the platform Tegra5 to fit in with what seems to be the naming scheme
for the other Tegra SOCs.

BUG=chrome-os-partner:25355
TEST=Built and ran on nyan and saw the "platform_family" setting return Tegra5
instead of (error).
BRANCH=None

Change-Id: I1044f958ecdac37ad285fdc3d53e7bc36ca69315
Signed-off-by: Gabe Black <5c8aa1266c03186393d9e7b3b4e3b14239af8201@google.com>
Reviewed-on: https://chromium-review.googlesource.com/184051
Reviewed-by: Hung-Te Lin <8a7fce4940baad93a69f5073b383c85deed9d9c4@chromium.org>
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>
Tested-by: Gabe Black <5c8aa1266c03186393d9e7b3b4e3b14239af8201@chromium.org>
Commit-Queue: Gabe Black <5c8aa1266c03186393d9e7b3b4e3b14239af8201@chromium.org>

ccaapton/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,coreboot/vboot,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,coreboot/vboot,geekboxzone/mmallow_external_vboot_reference,acorn-marvell/vboot_reference,acorn-marvell/vboot_reference,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference,ccaapton/vboot_reference,coreboot/vboot,acorn-marvell/vboot_reference,ccaapton/vboot_reference,geekboxzone/mmallow_external_vboot_reference