buildgcc: Show excessive arguments and bail out

Also remove a dead line that checks for unknown options: We already let
`getopt` check that.

Change-Id: I0e829b266e192757d6e455ee4cc608315bb4b7be
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/16681
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
1 file changed