ASoC: msm: Moving the gpio request and free in init and exit.

For every session startup and end the gpio request and the gpio
free occurs.
Moving the gpio request to init and gpio free to remove function
respectively to avoid the overhead of request and free for every
session established and tear downed.

CRs-Fixed: 405837
Change-Id: Ibf5c896a1fedb5d52e7f46d2d27ff6d64f65872e
Signed-off-by: Aviral Gupta <aviralg@codeaurora.org>