fsldma: clean up the OF subsystem routines

This fixes some errors in the cleanup paths of the OF subsystem, including
missing checks for ioremap failing. Also, some variables were renamed for
brevity.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --cc drivers/dma/fsldma.c
Simple merge

diff --cc drivers/dma/fsldma.h
Simple merge