ASoC: rt1015: remove possible unused variable `bclk_ms'

bclk_ms is possible unused by using the given config (see [1]).

sound/soc/codecs/rt1015.c:724:2: warning: Value stored to 'bclk_ms' is
never read [clang-analyzer-deadcode.DeadStores]
           bclk_ms = frame_size > 32;
           ^         ~~~~~~~~~~~~~~~

In addition, bclk_ms is meaningless and confusing after applying commit
a5db2ca5

 ("ASoC: rt1015: remove unneeded variables in rt1015_priv").
The "> 32" in the expression looks like a typo but it was not.

Let's remove the confusing variable bclk_ms.

[1]: https://lkml.org/lkml/2021/8/23/305

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20210823153323.1297723-1-tzungbi@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>