thermal: imx_tmu: Move architecture code into driver

Stop polluting the architecture directory with driver specific code,
move it into driver where it should be. Split the code slightly so
the MX8MM/MX8MN fuse readout and programming and MX8MP fuse readout
and programming are in their separate functions, and called in case
of matching SoC.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Andrejs Cainikovs <andrejs.cainikovs@toradex.com>