ASoC: max98926: Fix blr_clk_ratio calculation

Current code calculates blr_clk_ratio before setting max98926->ch_size, fix
it.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: anish kumar <yesanishhere@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>