crypto/internal/nistec: golang: Timing sidechannel for P-256 on ppc64le in crypto/internal/nistec

A flaw was found in the Golang crypto/internal/nistec package. Due to the usage of a variable time instruction in the assembly implementation of an internal function, a small number of bits of secret scalars are leaked on the ppc64le architecture. Considering how this function is used, this leaka...