soc: qcom: common_log: Support for memory dump v2

Register log_buf and log_first_idx with the memory dump v2 driver
to support log_buf parsing for targets using the enhanced memory
dump v2 format.

Change-Id: Idb4e70cc0c96c9621ae394b606ca3f6d9e32e32d
Signed-off-by: Jin Wu <jinw@codeaurora.org>