soc: nxp: lpc55xxx: fix dependencies for SOC_FLASH_MCUX

SOC_FLASH_MCUX has additional dependencies for LPC55xxx CPUs, due to the
fact that the flash should be disabled when executing in nonsecure mode.

Since the merge of HWMv2, this dependency has been set incorrectly at
the SOC level, resulting in the IAP flash driver being enabled when
targeting CPU1, which is incorrect. Fix the Kconfig dependency to
resolve this issue.

Fixes #79576

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>