Convert mx23/mx28 dts filed to use the pinctrl header files.

NOTE: During automatic conversion of these files to use the pinconfig
definitions an inconsistency has been found in:
arch/arm/boot/dts/imx28-apx4devkit.dts

According to the comment the function for pad SSP2_SS0 should have
been MX28_PAD_SSP2_SS0__GPIO_2_19, while the given value 0x2131
represents: MX28_PAD_SSP2_SS0__AUART3_TX

I used the later (though probably wrong) definition because that's
what is actually being used in the DTB.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

hog_pins is used to setup the pin functions, and it is not neccesarily used only
for GPIO pins, so use only 'hog' to describe a more generic term.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

For non-DT boot, function tx28_add_fec0 configures all ENET0 pins
into gpio mode for resetting fec phy, and then reconfigures those pins
into ENET function after that.

For DT boot, all the pin configuration is done by pinctrl subsystem.
Ideally, when gpio_request gets called, GPIO subsystem should call
pinctrl to configure pins into gpio mode automatically, and have pins
freed up from pinctrl subsystem when gpio_free is called.  But right
now, this cooperation between gpio and pinctrl hasn't been available.
As the result, we have to explicitly call pinctrl_get_select and
pinctrl_put for device tree boot.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Acked-by: NLothar Waßmann <LW@KARO-electronics.de>

Rename mxs dts files with soc name being the prefix, so that the board
dts file can be located easily by soc name, and we also gain the
consistency of naming.
Suggested-by: NMarek Vasut <marex@denx.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>

FEC support is missing because we need to find a proper way to rewrite
tx28_add_fec0 for device tree boot.

Cc: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>