DaVinci: EDMA: Updating default queue handling

EDMA queues in DM365 are a little different than those
on other DaVinci's. On DM365 Q0 and Q1 have the larger
FIFO size. We want Q0 and Q1 to be used by codecs and
DVSDK demos.
MMC driver is the only driver which uses the flag
'EVENTQ_DEFAULT'. So MMC driver should be using Q2 instead of
Q1 on DM365.
This patch allows us to declare a "default queue" from
SOC specific code. If it is not declared then the EDMA
driver assumes a default of queue 1.

Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>