ARM: msm: Don't use function labels for v2p translation

Using a function label for virt to phys translations causes
problems on THUMB2 kernels because the assembler will OR in a 1
at the bottom of the address when we ldr the label. Avoid this
problem by using a local variable and label that we can use to
calculate the amount we should subtract from the virtual address
to get the physical address. This should work for both ARM and
THUMB2 kernels.

Change-Id: Ifdd6120fd79711b99f0b358792b3b76f66ce48bb
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>