[PATCH] ppc32: add "indirect" DCR access, pass 2

[PATCH] ppc32: add "indirect" DCR access, pass 2

From: Matt Porter <mporter@kernel.crashing.org>

DCR number is encoded in mfdcr/mtdcr command itself and this prevents easy
DCR access when register number is not known on compile time.  This patch
adds __mfdcr & __mtdcr helpers which use pre-generated mfdcr/mtdcr
sequences for all possible DCR numbers.  We also use GCC extension
__builtin_constant_p to optimize cases when DCR number is in fact known
during compilation.

Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>