Build modules specific to imx5/imx6 only when building those kernels.

This adds sys/modules/imx with a SUBDIR makefile to make the whole
collection of modules that are specific to these SoCs.  Initially, that
"whole collection" consists of the if_ffec and imx_i2c drivers.

The if_ffec driver is referenced in its existing home in ../ffec rather
than moving it into the imx directory, because it's used by powerpc too,
but it is no longer built for all armv6/7 systems.

The imx_i2c driver is newly added as a module.

sys/arm/conf/IMX53

@@ -117,6 +117,6 @@ device		wlan_amrr		# AMRR transmit rate control algorithm
 
 # Flattened Device Tree
 options 	FDT			# Configure using FDT/DTB data
-makeoptions	MODULES_EXTRA=dtb/imx5
+makeoptions	MODULES_EXTRA="dtb/imx5 imx"
 
 options 	INTRNG

sys/arm/conf/IMX6

@@ -117,7 +117,7 @@ device		hdmi
 
 # Flattened Device Tree
 options 	FDT			# Configure using FDT/DTB data
-makeoptions	MODULES_EXTRA=dtb/imx6
+makeoptions	MODULES_EXTRA="dtb/imx6 imx"
 
 # SoC-specific devices
 device		ffec			# Freescale Fast Ethernet Controller

sys/modules/Makefile

@@ -813,10 +813,6 @@ _bcm283x_clkman=  bcm283x_clkman
 _bcm283x_pwm=  bcm283x_pwm
 .endif
 
-.if ${MACHINE_ARCH:Marmv[67]*} != ""
-_ffec=		ffec
-.endif
-
 SUBDIR+=${MODULES_EXTRA}
 
 .for reject in ${WITHOUT_MODULES}

sys/modules/imx/Makefile

@@ -0,0 +1,8 @@
+# $FreeBSD$
+# Build modules specific to freescale/nxp imx-family SoCs.
+
+SUBDIR = \
+	../ffec \
+	imx_i2c \
+	
+.include <bsd.subdir.mk>

sys/modules/imx/imx_i2c/Makefile

@@ -0,0 +1,15 @@
+# $FreeBSD$
+
+.PATH: ${SRCTOP}/sys/arm/freescale/imx
+
+KMOD=	imx_i2c
+SRCS=	imx_i2c.c
+
+SRCS+=	\
+	bus_if.h \
+	device_if.h \
+	iicbus_if.h \
+	ofw_bus_if.h \
+	opt_platform.h \
+
+.include <bsd.kmod.mk>