rpm-smd: Optimize smd data read

Replace completion event for tasklets such that the data read happens on
the same cpu and there is no delay in scheduling the task.

Change-Id: I47e3bc5436c1734a2c88df3b01197bc7b22fef99
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>