[POWERPC] Consolidate some of kernel/misc*.S

There were some common functions (mainly i/o).

Also some small white space cleanups and remove a couple of small unused
functions.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --cc arch/powerpc/kernel/Makefile
Simple merge

diff --cc arch/powerpc/kernel/misc.S
Simple merge

diff --cc arch/powerpc/kernel/misc_32.S
Simple merge

diff --cc arch/powerpc/kernel/misc_64.S
Simple merge