ASoC: rt5665: Fix uninitialized warning in rt5665_i2s_pin_event()

With gcc 4.1.2:

    sound/soc/codecs/rt5665.c: In function ‘rt5665_i2s_pin_event’:
    sound/soc/codecs/rt5665.c:2610: warning: ‘mask1’ may be used uninitialized in this function
    sound/soc/codecs/rt5665.c:2610: warning: ‘val2’ may be used uninitialized in this function
    sound/soc/codecs/rt5665.c:2610: warning: ‘val1’ may be used uninitialized in this function

The first one is currently a false positive, as rt5665_i2s_pin_event()
is never called with snd_soc_dapm_widget.shift set to a value not
handled by the switch() statement.  But that may change, so
preinitialize mask1 to fix this, like is already done for mask2.

The last two are false-positives, the compiler is just not smart enough
to notice the mask and val variables are always used together.

Fixes: 9b5d3865

 ("ASoC: rt5665: set i2s pin share configuration")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@kernel.org>