mtd: nand: omap: updated devm_xx for all resource allocation and free calls
"Managed Device Resource" or devm_xx calls takes care of automatic freeing
of the resource in case of:
- failure during driver probe
- failure during resource allocation
- detaching or unloading of driver module (rmmod)
Reference: Documentation/driver-model/devres.txt
Though OMAP NAND driver handles freeing of resource allocation in most of
the cases, but using devm_xx provides more clean and effortless approach
to handle all such cases.
- simplifies label for exiting probe during error
s/out_release_mem_region/return_error