m68knommu: fix misnamed GPIO pin definition for ColdFire 528x CPU

Compiling for a ColdFire 528x CPU will result in:

arch/m68k/platform/coldfire/m528x.c: In function ‘m528x_uarts_init’:
arch/m68k/platform/coldfire/m528x.c:72: error: ‘MCF5282_GPIO_PUAPAR’ undeclared (first use in this function)
arch/m68k/platform/coldfire/m528x.c:72: error: (Each undeclared identifier is reported only once
arch/m68k/platform/coldfire/m528x.c:72: error: for each function it appears in.)

The MCF5282_GPIO_PUAPAR definition changed names in the ColdFire definitions
cleanup. It is now MCFGPIO_PUAPAR, so change it.

Not sure how this one got missed, 2 lines below it is the correct use of
this definition.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>