RealView: Select CPU_V6 for MACH_REALVIEW_PB11MP

This seems to be missing from the arm:devel branch, though the other
RealView configurations were modified accordingly.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm/mach-realview/Kconfig

@@ -32,6 +32,7 @@ config REALVIEW_EB_ARM11MP_REVB
 
 config MACH_REALVIEW_PB11MP
 	bool "Support RealView/PB11MPCore platform"
+	select CPU_V6
 	select ARM_GIC
 	help
 	  Include support for the ARM(R) RealView MPCore Platform Baseboard.