Revert "avcodec/Makefile: fix checkheaders for nvenc_b"

This reverts commit 3be811a5.
Signed-off-by: NPhilip Langdale <philipl@overt.org>

libavcodec/Makefile

@@ -886,8 +886,6 @@ SKIPHEADERS-$(CONFIG_D3D11VA)          += d3d11va.h dxva2_internal.h
 SKIPHEADERS-$(CONFIG_DXVA2)            += dxva2.h dxva2_internal.h
 SKIPHEADERS-$(CONFIG_LIBSCHROEDINGER)  += libschroedinger.h
 SKIPHEADERS-$(CONFIG_LIBUTVIDEO)       += libutvideo.h
-SKIPHEADERS-$(CONFIG_H264_NVENC_ENCODER) += nvenc_b.h
-SKIPHEADERS-$(CONFIG_HEVC_NVENC_ENCODER) += nvenc_b.h
 SKIPHEADERS-$(CONFIG_QSV)              += qsv.h qsv_internal.h
 SKIPHEADERS-$(CONFIG_QSVDEC)           += qsvdec.h
 SKIPHEADERS-$(CONFIG_QSVENC)           += qsvenc.h