As some more information is added to the PCR register, we'd better use
a copy of its content and modify just the peripheral-related bits.
Implement a read-modify-write for the enable() and disable() callbacks.
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>