toolchain.inc: Test for valid toolchain when ANY_TOOLCHAIN is used

Even when ANY_TOOLCHAIN is selected, a valid compiler for the requested
architecture is needed.

Change-Id: If1a0a1ca6b726e8e58d29c69de93546510582548
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12681
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed