spi: spi-ep93xx: remove io wrappers

The io wrappers just add obfuscation to the driver. Remove them.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Mark Brown <broonie@kernel.org>