include/iterators.h: fix checkpatch.pl warnings

include/iterators.h: fix checkpatch.pl warnings

This patch introduces coding style changes such as reverse xmas tree
local variable declarations, header file reordering, and many other
minor tweaks such as line spacing, removing trailing white spaces.

In summary, this patch fixes the following checkpatch.pl
recommendations:
total: 0 errors, 25 warnings, 432 lines checked

Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>