linux-wandboard

powerpc/fsl: use of_iomap() for rstcr mapping

The rstcr register mapping code was written sometime ago before
of_iomap() existed.  We can use it and clean up the code a bit
and get rid of one user of get_immrbase() in the process.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>