[RISCV] Generate bexti for (select(setcc eq (and x, c))) where c is power of 2. (#73649)

Currently, llvm can transform (setcc ne (and x, c)) to (bexti x,
log2(c)) where c is power of 2.
This patch transform (select (setcc ne (and x, c)), T, F) into (select
(setcc eq (and x, c)), F, T).
It is benefit to the case c is not fit to 12-bits.