target/ppc: Check DEXCR on hash{st, chk} instructions

target/ppc: Check DEXCR on hash{st, chk} instructions

Adds checks to the hashst and hashchk instructions to only execute if
enabled by the relevant aspect in the DEXCR and HDEXCR.

This behaviour is guarded behind TARGET_PPC64 since Power10 is
currently the only implementation which has the DEXCR.

Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Message-Id: <20221220042330.2387944-3-nicholas@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>