extcon: ptn5150: fix COMPILE_TEST dependencies

The PTN5150 dependencies look like they were meant to do the
right thing, but they actually should not allow building without
I2C for compile testing, as that results in a Kconfig warning
and subsequent build failure:

WARNING: unmet direct dependencies detected for REGMAP_I2C
  Depends on [m]: I2C [=m]
  Selected by [y]:
  - EXTCON_PTN5150 [=y] && EXTCON [=y] && (I2C [=m] && GPIOLIB [=y] || COMPILE_TEST [=y])
  Selected by [m]:
  - EEPROM_AT24 [=m] && I2C [=m] && SYSFS [=y]
  - KEYBOARD_CAP11XX [=m] && !UML && INPUT [=y] && INPUT_KEYBOARD [=y] && OF [=y] && I2C [=m]
  - INPUT_DRV260X_HAPTICS [=m] && !UML && INPUT_MISC [=y] && INPUT [=y] && I2C [=m] && (GPIOLIB [=y] || COMPILE_TEST [=y])
  - ... [many others]

Add parentheses around the expression so we can compile-test
without GPIOLIB but not without I2C.

Fixes: 4ed754de ("extcon: Add support for ptn5150 extcon driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>