ASoC: wcd9335: Remove insert flag check in HS detection

Remove the insert_detect flag check in headset detection.
This flag is set in legacy mbhc config from machine driver.
Hence removing where latest mbhc driver is used.

Change-Id: If36571d90c1c3ac2693ebc263250a4e92aec2f60
Signed-off-by: Viraja Kommaraju <virajak@codeaurora.org>