ASoC: rt5514: Fix rt5514_spi_burst_read() buffer passing

rt5514_dsp_voice_wake_up_put() passes "(u8 *)&buf" to
rt5514_spi_burst_read(), where the cast is needed to silence a compiler
warning:

    sound/soc/codecs/rt5514.c: In function ‘rt5514_dsp_voice_wake_up_put’:
    sound/soc/codecs/rt5514.c:357: warning: passing argument 2 of ‘rt5514_spi_burst_read’ from incompatible pointer type

However, as the variable is declared as an array ("u8 buf[8]"), the
function should just pass "buf" instead.

Fixes: fc9cab05 ("ASoC: rt5514: The DSP clock can be calibrated by the other clock source")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@kernel.org>