ARM: edma: Convert to devm_* api

Use devm_ioremap_resource instead of reques_mem_region()/ioremap(),
devm_request_irq() instead of request_irq() and kzalloc() calls to
devm_kzalloc().

This ensures more consistent error values and simplifies error paths.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
[nsekhar@ti.com: add missing err.h include]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>