of/irq: Correct element count for array @dummy_imask in API of_irq_parse_raw()

Array @dummy_imask only needs MAX_PHANDLE_ARGS elements, but it actually
has (MAX_PHANDLE_ARGS + 1) elements. One extra element doesn't hurt
anything except for some stack usage.

Fix by using (MAX_PHANDLE_ARGS - 1) as max element index in initializer.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20241209-of_irq_fix-v1-2-782f1419c8a1@quicinc.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>