media: dvb: Fix support for maximum TSPP buffer size

The maximum allowed buffer size depends on maximum allowed
number of BAM descriptors. The maximum allowed number of
descriptors was changed to meet HW capabilities. A check
whether user buffer size requires number of descriptors
larger than what is allowed was added.

Change-Id: Ic60414af156ee8d969263b7636393693277c8f61
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>