avcodec/nvenc: use AVERROR_BUFFER_TOO_SMALL instead of ENOBUFS

Should fix compilation with mingw32
Reviewed-by: Timo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/nvenc.c

@@ -114,7 +114,7 @@ static const struct {
     { NV_ENC_ERR_ENCODER_NOT_INITIALIZED,  AVERROR(EINVAL),  "encoder not initialized"  },
     { NV_ENC_ERR_UNSUPPORTED_PARAM,        AVERROR(ENOSYS),  "unsupported param"        },
     { NV_ENC_ERR_LOCK_BUSY,                AVERROR(EAGAIN),  "lock busy"                },
-    { NV_ENC_ERR_NOT_ENOUGH_BUFFER,        AVERROR(ENOBUFS), "not enough buffer"        },
+    { NV_ENC_ERR_NOT_ENOUGH_BUFFER,        AVERROR_BUFFER_TOO_SMALL, "not enough buffer"},
     { NV_ENC_ERR_INVALID_VERSION,          AVERROR(EINVAL),  "invalid version"          },
     { NV_ENC_ERR_MAP_FAILED,               AVERROR(EIO),     "map failed"               },
     { NV_ENC_ERR_NEED_MORE_INPUT,          AVERROR(EAGAIN),  "need more input"          },