ASoC: stm: Prevent potential division by zero in stm32_sai_mclk_round_rate()

This patch checks if div is less than or equal to zero (div <= 0). If
div is zero or negative, the function returns -EINVAL, ensuring the
division operation (*prate / div) is safe to perform.

Signed-off-by: Luo Yifan <luoyifan@cmss.chinamobile.com>
Link: https://patch.msgid.link/20241106014654.206860-1-luoyifan@cmss.chinamobile.com


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