Introduce local variable 'struct device *dev' and use it instead of
dereferencing it repeatedly.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>