LU-6142 obdclass: use cl_object_for_each more broadly.

LU-6142 obdclass: use cl_object_for_each more broadly.

There are several loops which follow the pattern of the macros
cl_object_for_each() or cl_object_for_each_reverse(), but
don't use those macros.

Change to use the macros.  In some case we change the name of an 'obj'
arg to a function to 'top', to avoid overloading the name 'obj'.

Also include some minor formatting improvements.

Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I544d4148719a9284f33fd61730bd733c0d40e97c
Reviewed-on: https://review.whamcloud.com/39391
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>