powerpc/85xx: enable MTD options in sbc8548 defconfig

powerpc/85xx: enable MTD options in sbc8548 defconfig

This board has soldered on flash, and a SODIMM flash module.
Both can be used for booting, via switching JP12 and SW2.8
and using the sbc8548-altflash.dts when booting from SODIMM.

Here we enable MTD in kernel so that we can see the bootloader
(and other flash sectors) from linux.

Normal configuration:

 root@sbc8548:~# cat /proc/mtd
 dev:    size   erasesize  name
 mtd0: 007a0000 00020000 "space"
 mtd1: 00060000 00020000 "bootloader"
 mtd2: 03f00000 00080000 "space"
 mtd3: 00100000 00080000 "bootloader"
 root@sbc8548:~# dd if=/dev/mtd1 count=1 bs=48|hexdump -C
 1+0 records in
 1+0 records out
 00000000  27 05 19 56 55 2d 42 6f  6f 74 20 32 30 31 32 2e  |'..VU-Boot 2012.|
 00000010  31 30 2d 64 69 72 74 79  20 28 4a 61 6e 20 31 39  |10-dirty (Jan 19|
 00000020  20 32 30 31 33 20 2d 20  31 39 3a 34 30 3a 31 31  | 2013 - 19:40:11|
 00000030
 root@sbc8548:~# dd if=/dev/mtd3 count=1 bs=48|hexdump -C
 1+0 records in
 1+0 records out
 00000000  27 05 19 56 55 2d 42 6f  6f 74 20 32 30 31 32 2e  |'..VU-Boot 2012.|
 00000010  31 30 2d 64 69 72 74 79  20 28 44 65 63 20 31 33  |10-dirty (Dec 13|
 00000020  20 32 30 31 32 20 2d 20  31 35 3a 30 30 3a 30 37  | 2012 - 15:00:07|
 00000030
 root@sbc8548:~#

Alternate configuration, with sbc8548-altflash.dts:

 root@sbc8548:~# cat /proc/mtd
 dev:    size   erasesize  name
 mtd0: 03f00000 00080000 "space"
 mtd1: 00100000 00080000 "bootloader"
 mtd2: 007a0000 00020000 "space"
 mtd3: 00060000 00020000 "bootloader"
 root@sbc8548:~# dd if=/dev/mtd1 count=1 bs=48|hexdump -C
 1+0 records in
 1+0 records out
 00000000  27 05 19 56 55 2d 42 6f  6f 74 20 32 30 31 32 2e  |'..VU-Boot 2012.|
 00000010  31 30 2d 64 69 72 74 79  20 28 44 65 63 20 31 33  |10-dirty (Dec 13|
 00000020  20 32 30 31 32 20 2d 20  31 35 3a 30 30 3a 30 37  | 2012 - 15:00:07|
 00000030
 root@sbc8548:~# dd if=/dev/mtd3 count=1 bs=48|hexdump -C
 1+0 records in
 1+0 records out
 00000000  27 05 19 56 55 2d 42 6f  6f 74 20 32 30 31 32 2e  |'..VU-Boot 2012.|
 00000010  31 30 2d 64 69 72 74 79  20 28 4a 61 6e 20 31 39  |10-dirty (Jan 19|
 00000020  20 32 30 31 33 20 2d 20  31 39 3a 34 30 3a 31 31  | 2013 - 19:40:11|
 00000030
 root@sbc8548:~#

Note that in the latter, the larger SODIMM device appears 1st,
as mtd0 and mtd1, as indicated in the sizes, and in the date
of the u-boot image.

The kernel configuration is the same in both cases; only the dtb
needs to be changed in accordance with the JP12/SW2.8 settings.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>