Clarify two identical changelog entries
Clarify two identical changelog entries

The contribution from #2663 was split in two: the crypto part was
mereged in 2.19.1 and the x509 part was merged after 2.20.0. Tweak the
wording of the changelog entries to specify which is which.

NXPmicro/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,NXPmicro/mbedtls