staging: kpc2000: kpc_spi: remove unnecessary cast in [read|write]_reg()

The kpc_spi driver unnecessarily casts from a (u64 __iomem *) to a (void
*) when invoking readq and writeq which both take a (void __iomem *) arg.
There is no need for this cast, and it actually harms us by discarding
the sparse cookie, __iomem. Make the driver stop performing this casting
operation.

Signed-off-by: Geordan Neukum <gneukum1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>