Merge remote-tracking branch 'remotes/quic/tags/pull-hex-20210629' into staging

Fixes for bugs found by inspection and internal testing
Tests added to tests/tcg/hexagon/misc.c

# gpg: Signature made Tue 29 Jun 2021 17:50:16 BST
# gpg:                using RSA key 7B0244FB12DE4422
# gpg: Good signature from "Taylor Simpson (Rock on) <tsimpson@quicinc.com>" [undefined]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 3635 C788 CE62 B91F D4C5  9AB4 7B02 44FB 12DE 4422

* remotes/quic/tags/pull-hex-20210629:
  Hexagon (target/hexagon) remove unused TCG variables
  Hexagon (target/hexagon) cleanup gen_store_conditional[48] functions
  Hexagon (target/hexagon) fix l2fetch instructions
  Hexagon (target/hexagon) fix bug in fLSBNEW*

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>