crossgcc: Add mipsel-elf as supported target

Change-Id: Icd8050d9193f9957468cfa13901ec14e993e50de
Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-on: http://review.coreboot.org/8630
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
1 file changed