remove current RTSP support

include/netfilter.mk

package/kernel/modules/netfilter.mk

target/linux/generic/patches-2.6.30/190-netfilter_rtsp.patch

target/linux/generic/patches-2.6.31/190-netfilter_rtsp.patch

target/linux/generic/patches-2.6.32/190-netfilter_rtsp.patch

target/linux/generic/patches-2.6.36/190-netfilter_rtsp.patch

target/linux/generic/patches-2.6.37/605-netfilter_rtsp.patch

target/linux/generic/patches-2.6.38/605-netfilter_rtsp.patch

target/linux/generic/patches-2.6.39/605-netfilter_rtsp.patch

target/linux/generic/patches-3.0/605-netfilter_rtsp.patch

target/linux/generic/patches-3.1/605-netfilter_rtsp.patch