esp: use wc_ConstantCompare.

[philljj]

Description

wolfcrypt exposes a constant compare wrapper now:

• memory.c: add wc_ConstantCompare wrapper. wolfssl#10867

Use it instead of our own.

Testing

make && make cppcheck && make unit-esp && LD_LIBRARY_PATH=/usr/local/lib ./build/test/unit-esp

[philljj]

Some of the tests are using old wolfssl

Configuration summary for wolfssl version 5.9.1
...
./src/wolfesp.c:1214:10: error: call to undeclared function 'wc_ConstantCompare'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
 1214 |     rc = wc_ConstantCompare(icv, hash, esp_sa->icv_len);
      |          ^
1 error generated.
gmake: *** [Makefile:860: build/test/unit-esp] Error 1

This will pass when the nightly branch is updated.

[Copilot]

Pull request overview

Updates wolfIP’s ESP HMAC ICV verification to use the newly exported wolfCrypt constant-time compare wrapper, removing the local duplicate implementation and aligning wolfIP with upstream wolfCrypt.

Changes:

• Removed the local esp_const_memcmp() constant-time compare helper.
• Switched ESP ICV verification to wc_ConstantCompare().

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