ASoC: msm: Fix for proxy tx port getting closed on rx close

- When afe_port_start is called for proxy01_rx it does nothing,
  instead proxy port is opened when afe_port_start is called
  for proxy01_tx, but the same was not handled in afe_close.
- Added the check to prevent closure of proxy port when its
  called for proxy01_rx or proxy02_tx.

Change-Id: I34301c6e608e838d4c42eb60a5ff8c4ce20beb87
Signed-off-by: Dhananjay Kumar <dhakumar@codeaurora.org>