ARM: mxs: Update DENX M28 machine and dts file

Update the mach-mxs machine by removing the enet_clkout(). The new
revision of the board doesn't need that. Also, update the DTS file
with all the new drivers pulled in the mainline recently, that is,
SPI, LRADC, USB.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>