build: Fix out-of-tree builds
Fixes:
In file included from ../../../include/osmocom/core/msgb.h:25:0,
from ../../../include/osmocom/sim/sim.h:4,
from ../../../src/sim/reader_pcsc.c:30:
../../../include/osmocom/core/bits.h:6:35: fatal error: osmocom/core/bit16gen.h: No such file or directory
#include <osmocom/core/bit16gen.h>
In file included from ../../include/osmocom/core/msgb.h:25:0,
from ../../utils/osmo-sim-test.c:26:
../../include/osmocom/core/bits.h:6:35: fatal error: osmocom/core/bit16gen.h: No such file or directory
#include <osmocom/core/bit16gen.h>
2 files changed