dxva2: Pass variable of correct type to IDirectXVideoDecoder_GetBuffer()

This avoids related incompatible pointer type warnings.
dxva2: Clean up definition of _WIN32_WINNT

Only set a value if _WIN32_WINNT is undefined or smaller than 0x0600. This is
cleaner than unconditional definition and avoids a number of redefinition
warnings. Also only define a value in one of the two dxva2 headers.
aac_adtstoasc_bsf: Return proper error code

Signed-off-by: Diego Biurrun <diego@biurrun.de>
mpeg4videodec: Fix low_delay error message

Signed-off-by: Diego Biurrun <diego@biurrun.de>
Merge commit '4600a85eaa6182e5a27464f6b9cae5a9ddbf3098'

* commit '4600a85eaa6182e5a27464f6b9cae5a9ddbf3098':
  dxva2: Pass variable of correct type to IDirectXVideoDecoder_GetBuffer()

Conflicts:
	libavcodec/dxva2_h264.c
	libavcodec/dxva2_mpeg2.c
	libavcodec/dxva2_vc1.c

See: 64c53fa16aeca9cadd48ccf607803d6e4d26cc4d
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'b8962d64cc71af241601bcab5c3fcdc5735ef4ae'

* commit 'b8962d64cc71af241601bcab5c3fcdc5735ef4ae':
  dxva2: Clean up definition of _WIN32_WINNT

Conflicts:
	libavcodec/dxva2.h

See: 89946c8403752fbb26234d98f780188df8951a2e
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '63f800ca5f4f6b38f3789a7edb03bfabe8bacdd2'

* commit '63f800ca5f4f6b38f3789a7edb03bfabe8bacdd2':
  aac_adtstoasc_bsf: Return proper error code

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit 'e205fe6831fe1b5445f7827b5c916425620b4ab5'

* commit 'e205fe6831fe1b5445f7827b5c916425620b4ab5':
  mpeg4videodec: Fix low_delay error message

Merged-by: Michael Niedermayer <michaelni@gmx.at>
Add missing changelog entry

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