dca: convert dca_default_coeffs to float.

Easier to read, modify, and avoids relying on an outdated table.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
Merge commit 'b6d5e6aa10a2f09351f287e876f7ed4504e1f75d'

* commit 'b6d5e6aa10a2f09351f287e876f7ed4504e1f75d':
  dca: convert dca_default_coeffs to float.

Conflicts:
	libavcodec/dcadata.h

Merged-by: Michael Niedermayer <michaelni@gmx.at>