hwmon: (smsc47m1) Rename global platform device variable

pdev is a bad name for a global variable. Still more as the driver has
functions where pdev is a local variable. Rename it to smsc47m1_pdev.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/68a959b56da7f9452557d08c72249182364b0dd0.1701957841.git.u.kleine-koenig@pengutronix.de


Signed-off-by: Guenter Roeck <linux@roeck-us.net>