[NFC][PowerPC] Rebase the anonymous xxeval patterns to use the new XXEvalPattern class (#151462)
This change rebases the anonymous `xxeval` patterns to use the new
XXEvalPattern class based on the [[PowerPC] Exploit xxeval instruction
for ternary patterns - ternary(A, X,
and(B,C))](https://github.com/llvm/llvm-project/pull/141733#top)
Co-authored-by: Tony Varghese <tony.varghese@ibm.com>