powerpc: Add pgprot_cached_noncoherent()

This adds a pgprot combination required by some cache-enabled IO device
mappings, such as Freescale datapath (QMan and BMan) portals.
Signed-off-by: Geoff Thorpe <geoff@geoffthorpe.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/pgtable.h

@@ -170,6 +170,9 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long addre
 #define pgprot_cached_wthru(prot) (__pgprot((pgprot_val(prot) & ~_PAGE_CACHE_CTL) | \
 				            _PAGE_COHERENT | _PAGE_WRITETHRU))
 
+#define pgprot_cached_noncoherent(prot) \
+		(__pgprot(pgprot_val(prot) & ~_PAGE_CACHE_CTL))
+
 #define pgprot_writecombine pgprot_noncached_wc
 
 struct file;