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
1. Since the baud rate in the ROM cannot be changed,
set the default baud rate of the 26Mhz version
of esp32c2 to 74800
2. Since the systimer configuration of the 26Mhz
version requires a non-integer systimer frequency
configuration, and this feature is not supported
in the current ROM, this option is disabled for
the 26Mhz version esp32c2
