power: max77693: fix simple_return.cocci warnings

drivers/power/max77693_charger.c:615:1-4: WARNING: end returns can be simpified

 Simplify a trivial if-return sequence.  Possibly combine with a
 preceding function call.
Generated by: scripts/coccinelle/misc/simple_return.cocci

CC: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>