m68knommu: fix wrong register offsets used for ColdFire 5272 multi-function pins

The registers used to configure and set the multifunction pins on the 5272
ColdFire are defined as absolute addresses. So the use of them does not need
to be offset relative to the peripheral region address.

Fix two cases of incorrect usage of these addresses. Both affect UART
initialization, one in the common UART pin setup code, the other in the
NETtel board specific UART signal handling.

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