staging: greybus: Inline gb_audio_manager_module()

Convert 'gb_audio_manager_module' from a macro to a static
inline function, to make the relevant types apparent in the
definition and to benefit from the type checking performed by
the compiler at call sites.

Signed-off-by: Sumitra Sharma <sumitraartsy@gmail.com>
Link: https://lore.kernel.org/r/7470bf9d9a57e8bf27e55bd5e3791c5e0ee31385.1679732179.git.sumitraartsy@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>