Revert "target/ppc: Move SPR_DSISR setting to powerpc_excp"

Revert "target/ppc: Move SPR_DSISR setting to powerpc_excp"

This reverts commit 336e91f85332dda0ede4c1d15b87a19a0fb898a2.

It breaks the --disable-tcg build:

 ../target/ppc/excp_helper.c:463:29: error: implicit declaration of
 function ‘cpu_ldl_code’ [-Werror=implicit-function-declaration]

We should not have TCG code in powerpc_excp because some kvm-only
routines use it indirectly to dispatch interrupts. See
kvm_handle_debug, spapr_mce_req_event and
spapr_do_system_reset_on_cpu.

We can re-introduce the change once we have split the interrupt
injection code between KVM and TCG.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Message-Id: <20211209173323.2166642-1-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>