kbuild: remove BSP_VARIANT Makefile variable

This wasn't being used anywhere and seems to be a legcy of old sanity tests.
By removing this x86 is no longer a special case.

Change-Id: I78c668a7d9e6bc7c7f60d91712c4c21c0121b7e2
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2 files changed