usb: sisusb_con: Use array_size() helper in memcpy()

Use array_size() helper instead of the open-coded version in memcpy().
These sorts of multiplication factors need to be wrapped in array_size().

This issue was found with the help of Coccinelle and, audited and fixed
manually.

Addresses-KSPP-ID: https://github.com/KSPP/linux/issues/83
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200615231827.GA21348@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/sisusbvga/sisusb_con.c

@@ -1226,7 +1226,7 @@ sisusbcon_font_set(struct vc_data *c, struct console_font *font,
 		sisusb->font_backup = vmalloc(array_size(charcount, 32));
 
 	if (sisusb->font_backup) {
-		memcpy(sisusb->font_backup, font->data, charcount * 32);
+		memcpy(sisusb->font_backup, font->data, array_size(charcount, 32));
 		sisusb->font_backup_size = charcount;
 		sisusb->font_backup_height = font->height;
 		sisusb->font_backup_512 = (charcount == 512) ? 1 : 0;