fix Kconfig for c28x
Sonst gibts eine Warning: "warning: (STM32_MUX && S32K_GPIO && MACH_C28x_GPIO) selects GPIO which has unmet direct dependencies (MACH_HAS_GPIO)"
Sonst gibts eine Warning: "warning: (STM32_MUX && S32K_GPIO && MACH_C28x_GPIO) selects GPIO which has unmet direct dependencies (MACH_HAS_GPIO)"