gcc: arc: bump to git commit c6227bc

This fixes two issues: one segmentation fault in GCC and one invalid code
generation. Those fix numerous autobuild failures, including:
http://autobuild.buildroot.net/results/715/7158a2a19da6bfa950125a951a39061ccaa73101/
http://autobuild.buildroot.net/results/9d4/9d4fbcb91cf76e01c833d70c401c0828ad37631a/
http://autobuild.buildroot.net/results/ef6/ef6a0e2d382ae202bb8f0e9fc9f5e48c90119faf/
http://autobuild.buildroot.net/results/276/27692619efee482cded56967017f260bd30eefe7/

Signed-off-by: Anton Kolesov <anton.kolesov@synopsys.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gcc/Config.in.host

@@ -96,7 +96,7 @@ config BR2_GCC_VERSION
 	default "4.6.4"     if BR2_GCC_VERSION_4_6_X
 	default "4.7.3"     if BR2_GCC_VERSION_4_7_X
 	default "4.8.2"     if BR2_GCC_VERSION_4_8_X
-	default "7466697995233cc3aab5b9427bf843e3c7fabd80" if BR2_GCC_VERSION_4_8_ARC
+	default "c6227bc154124e270f15793deddfa3fe18f7db54" if BR2_GCC_VERSION_4_8_ARC
 	default "b93bb009e021aba64dd4b8cdb0bbc5a176c55543" if BR2_GCC_VERSION_4_9_MICROBLAZE
 	default BR2_GCC_SNAP_DATE if BR2_GCC_VERSION_SNAP