shields: mcp2515: add support for Keyestudio CAN-BUS shield

Add support for the Keyestudio CAN-BUS shield (KS0411). This shield is
very similar to the DFRobot CAN-BUS shield v2.0.

Rename the MCP2515 devicetree nodes in order not to conflict with
on-chip CAN controllers and switch to specifying the sample point
instead of time quantas.

Signed-off-by: Henrik Brix Andersen <hebad@vestas.com>