firmware: qcom: tz_log: Change fixed TZ log driver parameters

Debug buffer size and cpu count parameters of TZ log driver are fixed
and these values are changing from target to target. This patch adds
changes to get the cpu count from TZ and reads the DT parameter to get
the TZ debug buffer size.

Change-Id: I0e7605b8816f188058ea3087a75b3b375684206d
Signed-off-by: Zhen Kong <zkong@codeaurora.org>