ASoC: msm8952: use devm_regulator_get to correct regulator ref

During bootup, probe function will get called multiple times until
sound card is registered. And it calls msm8952_init_wsa_switch_supply
for each probe. If registeration fails, it'll not call
regulator_put to decrease regulator ref. In regulator consumers,
there are multiple sound-msm-vdd-wsa-switch.
Use devm_regulator_get instead of regulator_get to correct regulator
ref.

Change-Id: Ie270d235102f784241e3bf9566b811bbda22e419
Signed-off-by: Meng Wang <mwang@codeaurora.org>