ASoC: msm: q6dspv2: avoid hw_params and hw_free for ASM loopback

ASM loopback does not need any HW parameters to be set from
userspace. Similarly, the HW free function is also not doing
anything in terms of closing the actual HW. Remove these
functions for ASM loopback driver.

Change-Id: I9ceac58a9a0d7f1910ca7d8bb6a4e05e681cef7c
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>