logging: Make it possible to print category/subsys and timestamps

We want to see from which category/subsystem a certain log message
is coming from and use a different timestamp format as well. Add
two new bitfields. This doesn't change the size of the structure
and on 32bit we still have 27bits left.

The extended timestamp will take preference over the current and
default timestamp format.

Fixes: SYS#602
logging: Call color only once and use the result

First we check if a color is defined and then we call it again
and use the result. Avoid the second call and use the result of
the previous call.
ipa: Make a reservation for the GSUP protocol

GSUP is a protocol to have the OpenBSC SGSN talk
to an exterbal system for 3GPP MAP connectivity.