imx: Use RTEMS GPIO driver instead of FreeBSD one

Update 3869

libbsd.py

@@ -671,7 +671,6 @@ class mmc_ti(builder.Module):
         )
         self.addKernelSpaceSourceFiles(
             [
-                'sys/arm/freescale/imx/imx_gpio.c',
                 'sys/arm/ti/ti_hwmods.c',
                 'sys/arm/ti/ti_sdhci.c',
                 'sys/dev/gpio/gpiobus.c',
@@ -686,6 +685,7 @@ class mmc_ti(builder.Module):
             [
                 'local/sdhci_if.c',
                 'local/gpiobus_if.c',
+                'sys/arm/freescale/imx/imx_rtems_gpio.c',
             ],
             mm.generator['source']()
         )