gcc: fixup "standard" gcc location after 'use default gcc 4.8.2 for microblaze'

Somehow the 'else' part got dropped from commit 3f82e9dbcd (use default gcc
4.8.2 for microblaze), breaking download for "normal" architectures.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gcc/gcc.mk

@@ -22,6 +22,7 @@ GCC_SITE = ftp://www.at91.com/pub/buildroot/
 else ifeq ($(BR2_arc),y)
 GCC_SITE = $(call github,foss-for-synopsys-dwc-arc-processors,gcc,$(GCC_VERSION))
 GCC_SOURCE = gcc-$(GCC_VERSION).tar.gz
+else
 GCC_SITE = $(BR2_GNU_MIRROR:/=)/gcc/gcc-$(GCC_VERSION)
 endif