* strdup() function is returning a malloced string
  which must be freed after use
* replace the strdup with direct use of strings to avoid heap allocation

> Direct leak of 23 byte(s) in 1 object(s) allocated from:
    > 0 0x7ffff745b9a7 in __interceptor_strdup ../../../../src/libsanitizer/asan/asan_interceptors.cpp:454
    > 1 0x555559e36f87 in RCconfig_nr_parallel /openair2/GNB_APP/gnb_config.c:2054
    > 2 0x555559e38ea3 in NRRCConfig /openair2/GNB_APP/gnb_config.c:2097
    > 3 0x555559155542 in get_options /executables/nr-softmodem.c:423
    > 4 0x555559155542 in main /executables/nr-softmodem.c:623
    > 5 0x7ffff5e29d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

> Direct leak of 14 byte(s) in 1 object(s) allocated from:
    > 0 0x7ffff745b9a7 in __interceptor_strdup ../../../../src/libsanitizer/asan/asan_interceptors.cpp:454
    > 1 0x555559e370c5 in RCconfig_nr_parallel /openair2/GNB_APP/gnb_config.c:2063
    > 2 0x555559e38ea3 in NRRCConfig /openair2/GNB_APP/gnb_config.c:2097
    > 3 0x555559155542 in get_options /executables/nr-softmodem.c:423
    > 4 0x555559155542 in main /executables/nr-softmodem.c:623
    > 5 0x7ffff5e29d8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58