ARM: dts: omap: am335x-cm-t335: Remove unused mcasp num-serializer property

ARM: dts: omap: am335x-cm-t335: Remove unused mcasp num-serializer property

The dtbs_check validation for am335x-cm-t335.dtb flags an error
for an unevaluated 'num-serializer' property in the mcasp0 node.

This property is obsolete; it is not defined in the davinci-mcasp-audio
schema and is not used by the corresponding (or any) driver.

Remove this unused property to fix the schema validation warning.

Fixes: 48ab364478e77 ("ARM: dts: cm-t335: add audio support")
Signed-off-by: Jihed Chaibi <jihed.chaibi.dev@gmail.com>
Link: https://lore.kernel.org/r/20250830215957.285694-1-jihed.chaibi.dev@gmail.com
Signed-off-by: Kevin Hilman <khilman@baylibre.com>