powerpc/spufs: Fix hash faults for kernel regions

Commit ac29c64089b7 ("powerpc/mm: Replace _PAGE_USER with
_PAGE_PRIVILEGED") swapped _PAGE_USER for _PAGE_PRIVILEGED, and
introduced check_pte_access() which denied kernel access to
non-_PAGE_PRIVILEGED pages.

However, it didn't add _PAGE_PRIVILEGED to the hash fault handler
for spufs' kernel accesses, so the DMAs required to establish SPE
memory no longer work.

This change adds _PAGE_PRIVILEGED to the hash fault handler for
kernel accesses.

Fixes: ac29c64089b7 ("powerpc/mm: Replace _PAGE_USER with _PAGE_PRIVILEGED")
Cc: [e-mail] # v4.7+
Signed-off-by: Jeremy Kerr <[e-mail]>
Reported-by: Sombat Tragolgosol <[e-mail]>
Reviewed-by: Aneesh Kumar K.V <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>

arch/powerpc/platforms/cell/spu_base.c

···
 	    (REGION_ID(ea) != USER_REGION_ID)) {
 
 		spin_unlock(&spu->register_lock);
-		ret = hash_page(ea, _PAGE_PRESENT | _PAGE_READ, 0x300, dsisr);
+		ret = hash_page(ea,
+				_PAGE_PRESENT | _PAGE_READ | _PAGE_PRIVILEGED,
+				0x300, dsisr);
 		spin_lock(&spu->register_lock);
 
 		if (!ret) {