ENGR00233494 EPDC: Driver only supports 16 LUTs

ENGR00233494 EPDC: Driver only supports 16 LUTs

This bug was introduced by ENGR00229290 which fixed
the problem of greater than 16 LUTs used when 5-bit
waveform loaded. The bug is that now the driver is also
restricted to using 16 LUTs in 4-bit mode.

The fix is to correct the test of the EPDC_FORMAT
register used to determine if a 5-bit waveform
is loaded.

Also removed the while loop in favor of a bitwise OR
used to determine if a chosen LUT has yet to be
acknowledged by the interrupt handler.

Signed-off-by: Michael Minnick <michael.minnick@freescale.com>