milkymist-vgafb: swap pixel data in source buffer

In commit fc97bb5ba3 the lduw_raw() call was
eliminated. But we are reading from the target buffer a 16-bit value, which
is in big-endian format. Therefore, use lduw_be_p() to read the value.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Michael Walle <michael@walle.cc>

hw/display/milkymist-vgafb_template.h

@@ -61,7 +61,7 @@ static void glue(draw_line_, BITS)(void *opaque, uint8_t *d, const uint8_t *s,
     uint8_t r, g, b;
 
     while (width--) {
-        memcpy(&rgb565, s, sizeof(rgb565));
+        rgb565 = lduw_be_p(s);
         r = ((rgb565 >> 11) & 0x1f) << 3;
         g = ((rgb565 >>  5) & 0x3f) << 2;
         b = ((rgb565 >>  0) & 0x1f) << 3;