ACPI: PMIC: Remove unneeded check in tps68470_pmic_opregion_probe()

In tps68470_pmic_opregion_probe() pointer 'dev' is compared to NULL which
is useless.

Fix this issue by removing unneeded check.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: e13452ac ("ACPI / PMIC: Add TI PMIC TPS68470 operation region driver")
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Aleksandr Mishin <amishin@t-argos.ru>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://patch.msgid.link/20240730225339.13165-1-amishin@t-argos.ru


[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>