staging: kpc2000: kpc_i2c: fail probe if unable to map I/O space

The kpc2000 driver does not verify whether or not mapping the I/O
space succeeded during probe time. Make the driver verify that the
mapping operation was successful before potentially using that area
in the future.

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