regulator: move the cpr-regulator driver to the drivers/regulator directory

Move the cpr-regulator driver from the arch/arm/mach-msm
directory into the drivers/regulator directory.  Moving this
driver out of the arch/arm/mach-msm directory allows it to be
shared with architectures other than 'arm'.  In particular,
moving it allows it to be used by arm64.

Change-Id: I0b487c7fae42c260e06f5b70d1716bfbef065f4b
Signed-off-by: David Collins <collinsd@codeaurora.org>