Adjust pitch for STI when ShadowFB is disabled

Hi.

X11 do work much faster on HPPA when shadow framebuffer is disabled
(at least its so on 712 and LASI 715, Artist video chip). A simple
window dragging in twm notes the difference.

However default pScrn->displayWidth = pScrn->virtualX in wsfb leads to
a garbled screen in this mode.

Here's the fix which corrects it:

--- wsfb_driver.c.orig  Sat Feb  6 06:02:19 2016
+++ /usr/xenocara/driver/xf86-video-wsfb/src/wsfb_driver.c       Sat
Feb  6 08:06:35 2016
@@ -749,6 +749,8 @@ WsfbPreInit(ScrnInfoPtr pScrn, int flags)
        /* Quirk for LUNA's framebuffer */
        if (fPtr->wstype == WSDISPLAY_TYPE_LUNA)
                pScrn->displayWidth = fPtr->linebytes * 8;
+       else if (fPtr->wstype == WSDISPLAY_TYPE_STI && !fPtr->shadowFB)
+               pScrn->displayWidth = fPtr->linebytes;

        /* Set the display resolution. */
        xf86SetDpi(pScrn, 0, 0);

No visible artifacts detected.

Tests on other machines with working X11 (CRX (720/735/750), Timber
(710, old 715) and EG (B-series)) are welcome.