firmware: qcom: Fix compile warnings

Fix the following compiler warning(s) from gcc 6.1.1 with -Werror enabled:

 drivers/firmware/qcom/tz_log.c:879:
   format '%d' expects argument of type 'int', but argument 3 has type
   'u64 {aka long long unsigned int}' [-Werror=format=]

Fixes: 122d2db5 ("firmware: qcom: Add TZ log driver snapshot")
Change-Id: Ic0dedbad6800d136b7b7b63af70de4ed35559832
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>