MIPS: Use USE_OF as the guard for appended dtb
MIPS: Use USE_OF as the guard for appended dtb

Since OF is now a user selectable symbol, the choice for appended dtb
support should only be visible when USE_OF is selected, as this
indicates actual machine support for device tree in MIPS.

Signed-off-by: Jonas Gorski <8a35dafb21031d5c8209b1c0c47aaf0390b56a0e@openwrt.org>
Cc: 562397917b9a8bf316569a848858b12fb417723f@linux-mips.org
Cc: Kevin Cernekee <3105dbb3dd63fbb4f6371cfb04adc6726f76c56b@gmail.com>
Cc: Florian Fainelli <59190c1867e3222b932a0de3c668eb2d980d69a2@gmail.com>
Cc: Zubair Lutfullah Kakakhel <ec72f352acb5332d4f13d5809ce8993e793f678d@imgtec.com>
Cc: James Hogan <547fa85bb3888a0222eed8ec39e36708605c6d53@imgtec.com>
Cc: John Crispin <be6487f9df4dce44a640672d6c07330104d43593@openwrt.org>
Cc: Ganesan Ramalingam <ce45ac5d228273be0b7c6ac73a2de1c8b8d572e2@broadcom.com>
Cc: Jayachandran C <1bc8cf2274d8680f3a9b88ac7b7d2a9e0d1d4ca2@broadcom.com>
Cc: Andrew Bresticker <6f9d97df82107736b1c4f0e11d74242c25499ec8@chromium.org>
Cc: James Hartley <9656dd1efcf43da7ee9c9a45b212b02529f17710@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11283/
Signed-off-by: Ralf Baechle <92f48d309cda194c8eda36aa8f9ae28c488fa208@linux-mips.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs