event/dlb2: add v2.5 queue depth functions

event/dlb2: add v2.5 queue depth functions

Update the low level hardware functions responsible for
getting the queue depth. The command arguments are also
validated.

The logic is very similar to what was done for v2.0,
but the new combined register map for v2.0 and v2.5
uses new register names and bit names.  Additionally,
new register access macros are used so that the code
can perform the correct action, based on the hardware.

Signed-off-by: Timothy McDaniel <timothy.mcdaniel@intel.com>