media: dvb: mpq: Set smaller descriptor size for section pipe

Section and PES/recording pipes had same descriptor sizes,
notification rate from BAM for both types was the same. Since
sections are lower-bitrate than PES/recording data, the descriptor
size for sections pipe was reduced to allow better responsiveness
to this kind of data.

Change-Id: I9ddbf0c01ce0c6f0c4a8f5113a18a671f0e7b497
Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>