mmc: cavium-octeon: remove nonsense variable coercion

In this function, the variable 'base' is already 'void __iomem *base',
and the return function 'devm_platform_ioremap_resource()' also returns
this type, so the mandatory definition here is redundant.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20200327043639.6564-1-tangbin@cmss.chinamobile.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>