mm: Remove examples from enum zone_type comment

We can't really list every setup in common code. On top of that they are
unlikely to stay true for long as things change in the arch trees
independently of this comment.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NNicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20201119175400.9995-8-nsaenzjulienne@suse.deSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>

include/linux/mmzone.h

@@ -354,26 +354,6 @@ enum zone_type {
 	 * DMA mask is assumed when ZONE_DMA32 is defined. Some 64-bit
 	 * platforms may need both zones as they support peripherals with
 	 * different DMA addressing limitations.
-	 *
-	 * Some examples:
-	 *
-	 *  - i386 and x86_64 have a fixed 16M ZONE_DMA and ZONE_DMA32 for the
-	 *    rest of the lower 4G.
-	 *
-	 *  - arm only uses ZONE_DMA, the size, up to 4G, may vary depending on
-	 *    the specific device.
-	 *
-	 *  - arm64 has a fixed 1G ZONE_DMA and ZONE_DMA32 for the rest of the
-	 *    lower 4G.
-	 *
-	 *  - powerpc only uses ZONE_DMA, the size, up to 2G, may vary
-	 *    depending on the specific device.
-	 *
-	 *  - s390 uses ZONE_DMA fixed to the lower 2G.
-	 *
-	 *  - ia64 and riscv only use ZONE_DMA32.
-	 *
-	 *  - parisc uses neither.
 	 */
 #ifdef CONFIG_ZONE_DMA
 	ZONE_DMA,