media: stm32-dcmi: add 8-bit Bayer formats support

Add BA81, GBRG, GRBG, RGGB formats in the list of
supported capture formats.

Signed-off-by: Alain Volmat <alain.volmat@st.com>
Acked-by: Hugues FRUCHET <hugues.fruchet@st.com>
Reviewed-by: Philippe CORNU <philippe.cornu@st.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>