pnm: remove duplicated check for maxval > 255

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/pnm.c

@@ -164,8 +164,7 @@ int ff_pnm_decode_header(AVCodecContext *avctx, PNMContext * const s)
             if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
                 avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
             } else if (avctx->pix_fmt == AV_PIX_FMT_RGB24) {
-                if (s->maxval > 255)
-                    avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
+                avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
             } else {
                 av_log(avctx, AV_LOG_ERROR, "Unsupported pixel format\n");
                 avctx->pix_fmt = AV_PIX_FMT_NONE;