The ECDSA peripheral before ECO5 of esp32h2 does not perform the ECDSA
sign operation in constant time. This allows an attacker to read the
power signature of the ECDSA sign operation and then calculate the
ECDSA key stored inside the eFuse. The commit adds a countermeasure
for this attack. In this case the real ECDSA sign operation is
masked under dummy ECDSA sign operations to hide its real power
signature
For ESP32-H2 case, the hardware k mode is always enforced through
efuse settings (done in startup code).
For ESP32-P4 case, the software k mode is not supported in the peripheral
itself and code was redundant.
