mfd: pm8921: Potential NULL dereference in pm8921_remove()

commit d6daef95127e41233ac8e2d8472d8c0cd8687d38 upstream.

We assume that "pmic" could be NULL and then dereference it two lines
later.  I fix this by moving the dereference inside the NULL check.

Fixes: c013f0a5 ('mfd: Add pm8xxx irq support')

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
[ @MSF-Jarvis: Resolve conflicts ]
Signed-off-by: Willy Tarreau <w@1wt.eu>

Change-Id: Ie2b05029ebb333f2ccb5e608561fbcd96e436de6