checkpatch: improve SUSPECT_CODE_INDENT test

Many lines exist like

	if (foo)
			bar;

where the tabbed indentation of the branch is not one more than the "if"
line above it.

checkpatch should emit a warning on those lines.

Miscellenea:

o Remove comments from branch blocks
o Skip blank lines in block

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>