As SR1.0 uses the current higher priority channel to send commands to
the firmware, take this into account when setting/getting the number
of channels to/from the user.

Based on the work of Roger Quadros in TI's 5.10 SDK [1].

[1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/?h=ti-linux-5.10.yCo-developed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>