ASoC: wcd9335: don't check for HPHL and HPHR for mono headset

when mono headset is connected, either of the HPHL
or HPHR channel is enabled. So don't check for
both if cable is mono headset, otherwise RX chain is left muted
and hence audio is not heard from headset.

CRs-Fixed: 1018104
Change-Id: I464c785eba28f02993042d220e5744025e2f9346
Signed-off-by: Yeleswarapu Nagaradhesh <nagaradh@codeaurora.org>