sh: Expose physical addressing mode through cpuinfo.

CPUs can be in either the legacy 29-bit or 32-bit physical addressing
modes. This follows the x86 approach of tracking the phys bits in cpuinfo
and exposing it to userspace through procfs.

This change was requested to permit kexec-tools to detect the physical
addressing mode in order to determine the appropriate address mangling.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/processor.h

@@ -89,6 +89,7 @@ struct sh_cpuinfo {
 	struct task_struct *idle;
 #endif
 
+	unsigned int phys_bits;
 	unsigned long flags;
 } __attribute__ ((aligned(L1_CACHE_BYTES)));