hw/display/qxl: Do not use C99 // comments

Do not use C99 // comments to fix the checkpatch.pl error

Signed-off-by: Hyman Huang <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-ID: <7d287eaf00e0b52b600431efd350b15a0b5b3544.1734633496.git.yong.huang@smartx.com>
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>

Author: HuangSuiXiao

hw/display/qxl.c

@@ -50,7 +50,7 @@
 #undef ALIGN
 #define ALIGN(a, b) (((a) + ((b) - 1)) & ~((b) - 1))
 
-#define PIXEL_SIZE 0.2936875 //1280x1024 is 14.8" x 11.9" 
+#define PIXEL_SIZE 0.2936875 /* 1280x1024 is 14.8" x 11.9" */
 
 #define QXL_MODE(_x, _y, _b, _o)                  \
     {   .x_res = _x,                              \