ASoC: qcom: qdsp6v2: fix crash due to asynchronous read/write

Whenever an async read command is issued to dsp when
the driver is not enabled, there is a crash in userspace.
The read command is disallowed in the driver and an error
is propagated to userspace which results in the crash.
The driver is re-enabled in a subsequent asynchronous write
command anyway, so the async read command can be allowed.
Ensure that read is allowed by removing a superfluous check.

CRs-Fixed: 675131
Signed-off-by: Satya Krishna Pindiproli <satyak@codeaurora.org>
Change-Id: I5d0598e37d08ac1090f98c24be49fd99c132e22f
(cherry picked from commit b9f8d2a454df11d4ea98082215963e71a4c017f2)