ASoC: wm8523: Fix array size for bclk_ratios

ARRAY_SIZE(bclk_ratios) returns 7 for current code, then it cannot catch
the error if "no matching BCLK/fs ratio". Fix it.

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