soc: ti: pruss: Allow compile-testing

Allow compile testing of TI PRU-ICSS Subsystem Platform drivers.
This allows for improved build-test coverage.

No functional change intended.

Signed-off-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230511-ti-pruss-compile-testing-v1-1-56291309a60c@kernel.org


Signed-off-by: Nishanth Menon <nm@ti.com>