staging: greybus: audio_gb.c: Change uint32_t to u32

Change uint32_t to u32, solved the issue reported by checkpatch.pl:

CHECK: Prefer kernel type 'u32' over 'uint32_t'
+			uint32_t *format, uint32_t *rate, u8 *channels,

CHECK: Prefer kernel type 'u32' over 'uint32_t'
+			uint32_t format, uint32_t rate, u8 channels,

Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Acked-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>