ARM: Avoid building unsafe kernels on OMAP2 and MX3

OMAP2 (armv6) and MX3 turn off support for the V6K instructions, which
when they include support for SMP kernels means that the resulting
kernel is unsafe on SMP and can result in corrupted filesystems as we
end up using unsafe bitops.

Re-enable the use of V6K instructions on such kernels, and let such
kernels running on V6 CPUs eat undefined instruction faults which will
be much safer than filesystem corruption.  Next merge window we can fix
this properly (as it requires a much bigger set of changes.)

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/Kconfig

@@ -405,7 +405,7 @@ config CPU_V6
 config CPU_32v6K
 	bool "Support ARM V6K processor extensions" if !SMP
 	depends on CPU_V6 || CPU_V7
-	default y if SMP && !(ARCH_MX3 || ARCH_OMAP2)
+	default y if SMP
 	help
 	  Say Y here if your ARMv6 processor supports the 'K' extension.
 	  This enables the kernel to use some instructions not present
@@ -416,7 +416,7 @@ config CPU_32v6K
 # ARMv7
 config CPU_V7
 	bool "Support ARM V7 processor" if ARCH_INTEGRATOR || MACH_REALVIEW_EB || MACH_REALVIEW_PBX
-	select CPU_32v6K if !ARCH_OMAP2
+	select CPU_32v6K
 	select CPU_32v7
 	select CPU_ABRT_EV7
 	select CPU_PABRT_V7