powerpc/nvram: Allow byte length reads from mmio NVRAM driver

Add a byte length read and write interface compatible with the
nvram_generic driver interface to the mmio driver.

Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 file changed