LU-9325 osd-ldisk: replace simple_strto* with kstr* functions

LU-9325 osd-ldisk: replace simple_strto* with kstr* functions

The parsing of mount parameters from the config llog is done in
some cases with simple_strto* which is considered obsolete.
Replace simple_strto* with the kstrto* equivalent functions.

Change-Id: I7c26d14d02828c9f9a96f31a086a65bb39f3ea87
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/40119
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>