power: supply: rt5033_charger: recognize EXTCON setting

CHARGER_RT5033 should honor the EXTCON setting to prevent these
build errors:

riscv64-linux-ld: drivers/power/supply/rt5033_charger.o: in function `.L33':
rt5033_charger.c:(.text.rt5033_charger_probe+0x578): undefined reference to `extcon_find_edev_by_node'
riscv64-linux-ld: drivers/power/supply/rt5033_charger.o: in function `.L0 ':
rt5033_charger.c:(.text.rt5033_charger_probe+0x64e): undefined reference to `devm_extcon_register_notifier_all'
riscv64-linux-ld: drivers/power/supply/rt5033_charger.o: in function `.L96':
rt5033_charger.c:(.text.rt5033_charger_extcon_work+0x32): undefined reference to `extcon_get_state'

Fixes: 12cc585f36b8 ("power: supply: rt5033_charger: Add cable detection and USB OTG supply")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jakob Hauser <jahau@rocketmail.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Lee Jones <lee@kernel.org>
Cc: linux-pm@vger.kernel.org
Link: https://lore.kernel.org/r/20230828224201.26823-1-rdunlap@infradead.org


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>