test: dm: pinmux: Handle %pa in pinctrl-single mux output

The pinctrl-single driver uses %pa to print register value
in its single_get_pin_muxing() output. Handle this properly
in the test based on CONFIG_PHYS_64BIT .

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Simon Glass <sjg@chromium.org>