ARM: shmobile: Make use of r8a7790_add_standard_devices()

Move non-PFC and non-GPIO devices off from r8a7790_pinmux_init()
and into r8a7790_add_standard_devices() which is the normal place
to keep regular devices in the legacy case.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>