20250107-clang-tidy-null-derefs

[douzzer]

src/tls.c: fix possible null deref in TLSX_UseCertificateStatusRequestV2().

wolfcrypt/src/pkcs12.c: fix possible null deref in PKCS12_CoalesceOctetStrings(), and fix spelling of PKCS12_ConcatenateContent().

These defects were newly detected by clang-tidy in llvm-core/clang-20.0.0_pre20250104:

/tmp/tmp.4346_11739/wolfssl_test_workdir.22472/wolfssl/wolfcrypt/src/pkcs12.c:1278:9: note: Null pointer passed to 2nd parameter expecting 'nonnull'
1278 |         XMEMCPY(&data[*idx], mergedData, mergedSz);
|         ^

/tmp/tmp.4346_11739/wolfssl_test_workdir.22472/wolfssl/src/tls.c:4319:16: note: Access to field 'next' results in a dereference of a null pointer (loaded from variable 'last')
4319 |         for (; last->next; last = last->next);
|                ^~~~

Tested with wolfssl-multi-test.sh ... clang-tidy-all-sp-all check-source-text.