crossgcc: binutils: Remove invalid enable-multilibs option

Looks like somewhere after the original implementation it was renamed to
--enable-multilib without the s.
'enable-multilibs' is not a valid option for binutils.

Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Change-Id: I105cc9fa489aed24905dedb785c70bc69ed18970
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65608
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Singer <felixsinger@posteo.net>
diff --git a/util/crossgcc/buildgcc b/util/crossgcc/buildgcc
index 03c24da..3830160 100755
--- a/util/crossgcc/buildgcc
+++ b/util/crossgcc/buildgcc
@@ -686,7 +686,7 @@
 		--target=${TARGETARCH} --enable-targets=${TARGETARCH}${ADDITIONALTARGET} \
 		--disable-werror --disable-nls --enable-lto --enable-gold \
 		--enable-interwork --enable-multilib \
-		--enable-plugins --enable-multilibs \
+		--enable-plugins \
 		CFLAGS="$HOSTCFLAGS" \
 		CXXFLAGS="$HOSTCFLAGS" \
 		|| touch .failed