config: CPU_SW_DOMAIN_PAN ^ UACCESS_WITH_MEMCPY

CONFIG_CPU_SW_DOMAIN_PAN is incompatible with CONFIG_UACCESS_WITH_MEMCPY,
so make the "depends on" rules reflect that.

See: https://github.com/raspberrypi/linux/issues/1381



Signed-off-by: Phil Elwell <phil@raspberrypi.org>