Merge patch series "Zbb string optimizations"

Heiko Stuebner <heiko@sntech.de> says:

From: Heiko Stuebner <heiko.stuebner@vrull.eu>

This series still tries to allow optimized string functions for specific
extensions. The last approach of using an inline base function to hold
the alternative calls did cause some issues in a number of places

So instead of that we're now just using an alternative j at the beginning
of the generic function to jump to a separate place inside the function
itself.

* b4-shazam-merge:
  RISC-V: add zbb support to string functions
  RISC-V: add infrastructure to allow different str* implementations

Link: https://lore.kernel.org/r/20230113212301.3534711-1-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>