ARM: dts: at91: sam9x60: fix mux-mask to match product's datasheet

Fix the whole mux-mask table according to datasheet for the sam9x60
product.  Too much functions for pins were disabled leading to
misunderstandings when enabling more peripherals or taking this table
as an example for another board.
Take advantage of this fix to move the mux-mask in the SoC file where it
belongs and use lower case letters for hex numbers like everywhere in
the file.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Fixes: 1e5f532c

 ("ARM: dts: at91: sam9x60: add device tree for soc and board")
Cc: <stable@vger.kernel.org> # 5.6+
Cc: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun@microchip.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20210310152006.15018-1-nicolas.ferre@microchip.com