X11DRV_DIB_SetImageBits_24/32: Fix the case for bits_per_pixel == 32
and negative lines.

graphics/x11drv/dib.c

diff --git a/graphics/x11drv/dib.c b/graphics/x11drv/dib.c
index 46bf1a4..7252269 100644
--- a/graphics/x11drv/dib.c
+++ b/graphics/x11drv/dib.c
@@ -936,7 +936,7 @@
                 }
             } else {
                 lines = -lines;
-                imageBits = (BYTE *)(bmpImage->data + (lines - 1)*bmpImage->bytes_per_line);
+                imageBits = (BYTE *)(bmpImage->data);
                 for (h = 0; h < lines; h++) {
                     for (x = left; x < dstwidth; x++, bits += 3) {
                         imageBits[(x << 2) + indA] = 0x00;
@@ -1094,7 +1094,7 @@
                 }
             } else {
                 lines = -lines;
-                imageBits = (BYTE *)(bmpImage->data + (lines - 1)*bmpImage->bytes_per_line);
+                imageBits = (BYTE *)(bmpImage->data);
                 for (h = 0; h < lines; h++) {
                     for (x = left; x < dstwidth; x++, bits += 4) {
                         imageBits[(x << 2) + indA] = 0x00;