ARM: iWMMXt: always enable iWMMXt support with PJ4 CPUs

Jason Cooper reports these build errors:
arch/arm/kernel/built-in.o: In function `iwmmxt_do':
/.../arch/arm/kernel/pj4-cp0.c:36: undefined reference to `iwmmxt_task_release'
/.../arch/arm/kernel/pj4-cp0.c:40: undefined reference to `iwmmxt_task_switch'
make: *** [vmlinux] Error 1

This is caused because the PJ4 code explicitly references the iWMMXt
code, but doesn't require it to be built.  Fix this by ensuring that
iWMMXt is always enabled with PJ4.
Reported-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -1183,9 +1183,9 @@ config ARM_NR_BANKS
 	default 8
 
 config IWMMXT
-	bool "Enable iWMMXt support"
+	bool "Enable iWMMXt support" if !CPU_PJ4
 	depends on CPU_XSCALE || CPU_XSC3 || CPU_MOHAWK || CPU_PJ4
-	default y if PXA27x || PXA3xx || ARCH_MMP
+	default y if PXA27x || PXA3xx || ARCH_MMP || CPU_PJ4
 	help
 	  Enable support for iWMMXt context switching at run time if
 	  running on a CPU that supports it.