device-tree: sam_70_xplained: added config for qdec

the device tree offers a default config (qdec0) for 1x qdec at TC0,
however does not offer a default config for qdec1 - qdec3.
this will be added with this commit. Fixes #65610

Signed-off-by: Sven Ginka <sven.ginka@gmail.com>