tspp: Improve data-path handling

Existing driver allocated BAM descriptor at fixed sizes each
with interrupt flag set. Notification on data was received when
the descriptor is fully consumed by the HW. The descriptor size
on one hand need to be big enough so that we don't receive too much
interrupts for high-bitrate streams, and on other hand needs
to be small enough so that for low-bitrate stream we are not starved
waiting for data for a long period of time.

The change adds support of allocating small descriptors and set
interrupt flags on part of descriptors. In addition, expiration
timer is used so that if interrupt is not received after long period
of time the timer handler reports back descriptors are already ready
to be consumed. This allows low-rate of interrupts and
handling of low-bitrate streams.

As descriptors are smaller now (size of single TS packet), exposed
API within SW demux that handles a single packet to save the function
call to the API that handles multiple packets for efficiency. Information
regarding the new buffer allocation was added to debugfs.

CRs-Fixed: 420818
Change-Id: I4bb05177774ab0e0bad0737ca1106a0c33f843ae
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>