altera_ps2: Add devicetree support

Add match table for device tree binding.

v2: use const and add compat version.
v3: change compatible vendor to ALTR.
    add dts binding doc.
v4: condition module device table export for of.

Signed-off-by: Walter Goossens <waltergoossens@home.nl>
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
[dustan.bower@gmail.com: fixed missing semicolon]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>