checkpatch: Use upstream commit text length checks

Upstream has merged a few commit text length checks
that make our own checks redundant. Furthermore,
upstream also has a newer exception list (such as
allowing Fixes: lines to be >75 characters) that
we should take advantage of.

Change-Id: I894482c1a4182ad71146d5d433610d4cb210cb1d
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>