ChangeLog.d/fix-declaration-of-mbedtls_ecdsa_sign_det_restartable-function.txt

Bugfix
   * Fix declaration of mbedtls_ecdsa_sign_det_restartable() function
     in the ecdsa.h header file. There was a build warning when the
     configuration macro MBEDTLS_ECDSA_SIGN_ALT was defined.
     Resolves #7407.