build system: mips is a valid nickname for mipsel

Change-Id: I5829a96cbb0af0398113efbdf34dfa3d102bf4c8
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: http://review.coreboot.org/9146
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)

util/xcompile/xcompile

@@ -209,10 +209,11 @@ arch_config_x86() {
 }
 
 arch_config_mipsel() {
-	TARCH="mipsel"
+	TARCH="mips"
 	TBFDARCHS="tradlittlemips littlemips"
 	TCLIST="mipsel"
 	TWIDTH="32"
+	TSUPP="mips mipsel"
 	TABI="elf"
 }