ARM: shmobile: Move pm-rcar.h, cleanup r8a7779 case

Change location of pm-rcar.h so it can be used as #include "pm-rcar.h"
instead of the old style #include <mach/pm-rcar.h>. Also clean up
the r8a7779 case to move some unused header file cruft into a C
file.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>