upgrade to 2.6.19.1, fix Gateway 7001 patch and enable image generation for ixp4xx

scripts/arm-magic.sh

target/linux/aruba-2.6/Makefile

target/linux/au1000-2.6/Makefile

target/linux/brcm-2.6/Makefile

target/linux/brcm63xx-2.6/Makefile

target/linux/ixp4xx-2.6/Makefile

target/linux/ixp4xx-2.6/config

target/linux/ixp4xx-2.6/image/Makefile

target/linux/ixp4xx-2.6/patches/200-gateway_7001.patch

...t/linux/ixp4xx-2.6/patches/900-no_loader_workaround.patch

target/linux/magicbox-2.6/Makefile

target/linux/rb532-2.6/Makefile

target/linux/rdc-2.6/Makefile

target/linux/sibyte-2.6/Makefile

target/linux/uml-2.6/Makefile

target/linux/x86-2.6/Makefile