libc_arm: avoid multiple version of __aeabi_unwind_cpp_pr dummy code

libc_arm: avoid multiple version of __aeabi_unwind_cpp_pr dummy code

Do not pollute libraries with its own implementation of __aeabi_unwind_cpp_pr1 code.
Just add it to uclibc_nonshared.a archive and share it.
This fixes build issue with static linking of application due to multiple symbol
definition in libgcc_eh-a and libpthread.a or librt.a

Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>