soc: qcom: glink_smem_native_xprt: Reset RPM indicies on init

The fifo to the RPM may have been used by the bootloader and therefore is
not guaranteed to be in the initialized state when the transport inits.

Reset the locally owned fifo indicies on init to ensure they start off
in the initialized state.

Change-Id: Ifae27ed75b544f42957b16f2d891771d3e09b5fd
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>