ASoC: stm32: sai: Remove useless define

STM_SAI_IS_SUB_B(x) and STM_SAI_BLOCK_NAME(x) are
not being used, so remove them.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Acked-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20220525135023.6792-1-tangbin@cmss.chinamobile.com


Signed-off-by: Mark Brown <broonie@kernel.org>