firmware: fix GOOGLE_SMI kconfig dependency warning

Is it meaningful/useful to enable EFI_VARS but not EFI?
That's what GOOGLE_SMI does.  Make it enable EFI also.

Fixes this kconfig dependency warning:

warning: (GOOGLE_SMI) selects EFI_VARS which has unmet direct dependencies (EFI)

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>