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: Ic8751b13af9d65d7eec494e1260d47c023c31ed0
Signed-off-by: Jin Wu <jinw@codeaurora.org>