ARM: shmobile: ape6evm: add MMCIF support

Add MMCIF support to the APE6EVM board in PIO mode only. Power supply is
fixed for now, eventually support for the tps80032 regulator, also
supplying both VDD and VccQ to the MMCIF slot should be added to APE6EVM.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>