platform: msm_shared: Wait for apps-rpm channel to be populated

Appsl runs & initializes SMD driver before rpm populates the channel
entries in SMEM. Due to this appsbl fails to fidn the apps-rpm
communication channel & halts. To void this race condition wait in appsbl
for channel entry to be populated in SMEM by rpm.

Change-Id: I045d29fd08b5ffbf383a901352f6d5accccfbb2f
2 files changed