qualcommax: use defines for MAC mode setting

qualcommax: use defines for MAC mode setting

Now that we have the MAC modes defined in DT bindings, lets replace all of
the raw hex values with defines.

While we are here, we can drop the disabled UNIPHY-s as that is the default
value in the ESS DTSI.

Signed-off-by: Robert Marko <robimarko@gmail.com>