mfd: lpc_ich: Fix gpio base and control offsets

In ICH5 and earlier the GPIOBASE and GPIOCTRL registers are found at
offsets 0x58 and 0x5C, respectively. This patch allows GPIO access to
properly be enabled (and disabled) for these chipsets.

Signed-off-by: Agócs Pál <agocs.pal.86@gmail.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>