Update Eigen to commit:954e21152e204b1960aca802eb9f16d054d70fd9

CHANGELOG
=========
954e21152 - Include <limits> in test main.h
e15cd620a - Remove select class
1c0048a08 - Fix inconsistency between ptrue and pcmp_* in HVX
ddce1d7d1 - Fixes #2952
8b9dbcdaa - Fix numext::bit_cast() compilation failure in C++20
975a5aba4 - Fix TODO: Use std::bit_cast or __builtin_bit_cast if available.

PiperOrigin-RevId: 794397153
Change-Id: I6acf902aeeafe4f69dd9fafefa9d823615d01970