dct/rdft: Remove duplicate typedefs for context structs

The typedefs also exist in the avfft.h header and since typedefs cannot be
legally redefined in C, the code fails to compile with some compilers.

This reverts commits 11c7155cce and 57f1b1dcc7.
qpeldsp: Mark source pointer in qpel_mc_func function pointer const
vc1dsp: Add wrappers for {avg|put}_vc1_mspel_mc00_c

This avoids invoking the wrapped functions with too many arguments.
Merge commit '060e4a9e0627adcda9101dd68ec7f22b4ce22b5b'

* commit '060e4a9e0627adcda9101dd68ec7f22b4ce22b5b':
  dct/rdft: Remove duplicate typedefs for context structs

See: 005e81d6cff4071847fe6e6b6de3b5d709c76de9
See: 77304cf3523cbeec56a29749fea5c21e610be644
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '7fb993d338d88f2f62e0a358b6c9f3eb9a3a08ac'

* commit '7fb993d338d88f2f62e0a358b6c9f3eb9a3a08ac':
  qpeldsp: Mark source pointer in qpel_mc_func function pointer const

Conflicts:
	libavcodec/h264qpel_template.c
	libavcodec/x86/cavsdsp.c
	libavcodec/x86/rv40dsp_init.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '58e65e44f435243dc72dfce1f8af8afcf1319f34'

* commit '58e65e44f435243dc72dfce1f8af8afcf1319f34':
  vc1dsp: Add wrappers for {avg|put}_vc1_mspel_mc00_c

Conflicts:
	libavcodec/vc1dsp.c

See: 319235c67c59d6abaa78d5af57121ab9816f937d
Merged-by: Michael Niedermayer <michaelni@gmx.at>
RELEASE_NOTES: fix WebVTT decoder typo (-> encoder)

Found-by: Clément Bœsch <u@pkh.me>
Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>