Reordered and packed sccp_global_vars struct to minimized size and lineup to 64 byte cache lines

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5230 43c1dc8c-776e-4df2-8ef1-6e829299be21
Rename sccp_channel_set_active to sccp_device_setActiveChannel. Only call sccp_channel_setActiveChannel from sccp_channel_setDevice, to make sure they are always updated at the same time (rb: 49)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@5231 43c1dc8c-776e-4df2-8ef1-6e829299be21