powerpc/8xx: Increase number of slices to 64

On the 8xx, the minimum slice size is the size of the area
covered by a single PMD entry, ie 4M in 4K pages mode and 64M in
16K pages mode.

This patch increases the number of slices from 16 to 64 on the 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/nohash/32/slice.h

@@ -4,7 +4,7 @@
 
 #ifdef CONFIG_PPC_MM_SLICES
 
-#define SLICE_LOW_SHIFT		28
+#define SLICE_LOW_SHIFT		26	/* 64 slices */
 #define SLICE_LOW_TOP		(0x100000000ull)
 #define SLICE_NUM_LOW		(SLICE_LOW_TOP >> SLICE_LOW_SHIFT)
 #define GET_LOW_SLICE_INDEX(addr)	((addr) >> SLICE_LOW_SHIFT)