iommu/msm: Deletion of unnecessary checks before clk_disable()

A semantic patch approach was proposed with the subject
"[PATCH with Coccinelle?] Deletion of unnecessary checks
before specific function calls" on 2014-03-05.
https://lkml.org/lkml/2014/3/5/344
http://article.gmane.org/gmane.comp.version-control.coccinelle/3513/

This patch pattern application was repeated with the help of
the software "Coccinelle 1.0.0-rc22" on the source files for
Linux 3.17.1. An extract of the automatically generated
update suggestions is shown here.

It was determined that the affected source code places call
functions which perform input parameter validation already.
It is therefore not needed that a similar safety check is
repeated at the call site.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Joerg Roedel <jroedel@suse.de>