uvesafb: add info about pmipal, yrap and ypan being available only on x86

index cfc4e55..1a3b65b 100644
@@ -59,11 +59,12 @@ Accepted options:
 ypan    Enable display panning using the VESA protected mode
         interface.  The visible screen is just a window of the
         video memory, console scrolling is done by changing the
-        start of the window.
+        start of the window.  Available on x86 only.
 
 ywrap   Same as ypan, but assumes your gfx board can wrap-around
         the video memory (i.e. starts reading from top if it
         reaches the end of video memory).  Faster than ypan.
+        Available on x86 only.
 
 redraw  Scroll by redrawing the affected part of the screen, this
         is the safe (and slow) default.

@@ -75,7 +76,7 @@ vgapal  Use the standard VGA registers for palette changes.
 
 pmipal  Use the protected mode interface for palette changes.
         This is the default if the protected mode interface is
-        available.
+        available.  Available on x86 only.
 
 mtrr:n  Setup memory type range registers for the framebuffer
         where n: