kmp204x/qrio: support for setting the CPU reset request mode

To acheive this, the qrio_uprstreq() function that sets the UPRSTREQN
flag in the qrio RESCNF reg is added.

Signed-off-by: Rainer Boschung <rainer.boschung@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Reviewed-by: York Sun <yorksun@freescale.com>