ARM: defconfig: pxa: Remove duplicate CONFIG_USB_GPIO_VBUS entry

ARM: defconfig: pxa: Remove duplicate CONFIG_USB_GPIO_VBUS entry

The pxa_defconfig file defines CONFIG_USB_GPIO_VBUS twice, first as
built-in ('y') and then as a module ('m'). The kconfig system correctly
uses the last definition, but the duplication is confusing.

Remove the obsolete configuration to resolve the ambiguity and clean
up the configuration.

Fixes: 2002f3968714 ("ARM: refresh defconfig files")
Signed-off-by: Jihed Chaibi <jihed.chaibi.dev@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>