ar71xx: add v3.18 support

target/linux/ar71xx/config-3.18

target/linux/ar71xx/files/arch/mips/ath79/dev-dsa.c

target/linux/ar71xx/files/drivers/gpio/gpio-nxp-74hc153.c

target/linux/ar71xx/files/drivers/net/dsa/mv88e6063.c

...102-MIPS-ath79-Avoid-using-unitialized-reg-variable.patch

...8/206-spi-ath79-make-chipselect-logic-more-flexible.patch

...x/patches-3.18/213-MIPS-ath79-fix-ar933x-wmac-reset.patch

...x/ar71xx/patches-3.18/220-add_cpu_feature_overrides.patch

...patches-3.18/300-MIPS-add-MIPS_MACHINE_NONAME-macro.patch

...x/ar71xx/patches-3.18/310-lib-add-rle-decompression.patch

...ar71xx/patches-3.18/401-mtd-physmap-add-lock-unlock.patch

...ux/ar71xx/patches-3.18/402-mtd-SST39VF6401B-support.patch

...tches-3.18/403-mtd_fix_cfi_cmdset_0002_status_check.patch

...nux/ar71xx/patches-3.18/404-mtd-wrt160nl-trx-parser.patch

...r71xx/patches-3.18/405-mtd-tp-link-partition-parser.patch

...-m25p80-allow-to-pass-probe-types-via-platform-data.patch

.../ar71xx/patches-3.18/408-mtd-redboot_partition_scan.patch

...linux/ar71xx/patches-3.18/409-mtd-rb4xx_nand_driver.patch

...linux/ar71xx/patches-3.18/410-mtd-rb750-nand-driver.patch

...tches-3.18/411-mtd-cfi_cmdset_0002-force-word-write.patch