gcc: disallow 4.9.x for ARM cortex-a72

a72 support was only added in the 5.1 cycle.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gcc/Config.in.host

@@ -41,7 +41,7 @@ choice
 		# Broken or unsupported architectures
 		depends on !BR2_arc && !BR2_bfin
 		# Broken or unsupported ARM cores
-		depends on !BR2_cortex_a17
+		depends on !BR2_cortex_a17 && !BR2_cortex_a72
 		# Unsupported MIPS cores
 		depends on !BR2_mips_interaptiv
 		# Unsupported for MIPS R5