correct type botch.  physical memory is "uintmem", and i should know that.

Reference: /n/atom/patch/applied/fsmmuppn
Date: Sat Aug 15 23:20:02 CES 2015
Signed-off-by: quanstro@quanstro.net

--- /sys/src/fs/amd64/mmu.c	Sat Aug 15 23:19:47 2015
+++ /sys/src/fs/amd64/mmu.c	Sat Aug 15 23:19:48 2015
@@ -51,7 +51,7 @@
  *	mmuptcopy (PteSHARED trick?);
  */
 
-#define PPN(x)		((x)&~(uintptr)(PGSZ-1))
+#define PPN(x)		((x)&~(uintmem)(PGSZ-1))
 
 /*
  * set up a pat mappings.  the system depends