The code in OCTET8 implementation assumes the len is placed inside the
byte preceding the memory buffer, which is true for the defined cases.
However, it creates a compilation warning. Better pass the value
directly from the struct field rather than playing addr games. this way
we also assert we require to explicitly pass the len.
Fixes lots of warning like the one below:
/home/pespin/dev/sysmocom/bin/../git/libsmpp34/src/smpp34_unpack.c: In function ‘smpp34_u
npack’:
/home/pespin/dev/sysmocom/bin/../git/libsmpp34/src/smpp34_unpack.c:147:14: warning: array
subscript is above array bounds [-Warray-bounds]
lenval = *((inst par) - 1);\
^~~~~~~~~~~~~~~~~
/home/pespin/dev/sysmocom/bin/../git/libsmpp34/def_frame/submit_sm.frame:18:2: note: in e
xpansion of macro ‘OCTET8’
OCTET8( instancia, short_message, 254 );
^~~~~~
Change-Id: Id110f4e977c3becdb44cf5492c372e530ea51551