soc: qcom: bam_dmux: Use uintptr_t for int <-> pointer conversions

Conversions between integers and pointers should use the uintptr_t type.

Use the uintptr_t type in conversions between pointers and integers where
necessary.

Change-Id: I3eed0e2791f02cbab5d7cf9d801ddc221c2ae098
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>