sim900: Fix minor coding style violation
call-forwarding: Minor style fixes
call-forwarding: Refactoring of is_cfu_enabled()

This also removes the need for uninitialized_var() macro.
call-forwarding: Update conditional setting logic

Due to how the quiescent behavior of conditional call forwarding rules
when CFU is active, do not allow the user to try and set conditional
rules.  This will fail at the network level anyway.
call-forwarding: Update conditional reporting logic

Don't report conditional cfs when cfu is active
call-forwarding: Emit signals when cfu is toggled

Emit signals to mask/unmask conditional cfs on cfu
activation/deactivation.
call-forwarding: Minor code refactoring
call-forwarding: Fix various style issues
hso: Don't access freed data, in hso_set_online
atutil: Ignore invalid CLCC results

Some phones report CLCC calls with out-of-range info.  E.g. call index
being 0 (it is 1 based according to 27.007) and call states being
reported as '6' (valid call states are 0-5.)
sms: Disable sending AT+CNMA with SIMCOM quirk

SIMCOM SIM900 modem module not support AT+CNMA command
sim900: Use SIMCOM quirk for SMS atom
Release 1.5
voicecall: Fix strange GTA04 modem CLCC behavior
emulator: fix notify_ring

notify_ring should not use information from waiting call
voicecall: Don't set indicators during transitions
sim900: Add ussd and voice call support
voicecall: Improve transitions check

Indicators should not be updated if:
- multiple separate calls are active at same time
- a conf call and a call are active at same time
- multiple separate calls are held at same time
- a conf call and a call are held at same time
- a conf call has call in active and held state
call-forwarding: Remove cf_list_clear()

Use g_slist_free_full() instead.
call-forwarding: Inline get_query_next_cf_cond()