msm: qdss: always start etb dump on a frame aligned address

ETB is disabled and flushed before dumping and the flush results in
the formatter inserting necessary padding when required to ensure
trace is terminated on a formatter frame boundary.

In case of an error causing the write pointer to not be formatter
frame aligned, ensure that we start the dump at the next aligned
address and manually pad the remaining bytes.

Change-Id: I7bacb088f13ff3b5acb7f21391625b0cd9150b2e
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>