Move reverse_bits*() to separate source file

reversing bits is not NR specific. Think of it like this: LTE code might
use reverse_bits*() as well, but in the old location, it would pull in a
bunch of NR dependencies that are superfluous.

common/utils/CMakeLists.txt

@@ -14,7 +14,7 @@ add_subdirectory(nr)
 add_subdirectory(LOG)
 add_subdirectory(threadPool)
 add_subdirectory(time_manager)
-add_library(utils utils.c system.c time_meas.c time_stat.c tuntap_if.c)
+add_library(utils utils.c system.c time_meas.c time_stat.c tuntap_if.c reverse_bits.c)
 target_include_directories(utils PUBLIC .)
 target_link_libraries(utils PRIVATE ${T_LIB})
 if (ENABLE_TESTS)