target/ppc: powerpc_excp: Set vector earlier

target/ppc: powerpc_excp: Set vector earlier

None of the interrupt setup code touches 'vector', so we can move it
earlier in the function. This will allow us to later move the System
Call Vectored setup that is on the top level into the
POWERPC_EXCP_SYSCALL_VECTORED code block.

This patch also moves the verification for when 'excp' does not have
an address associated with it. We now bail a little earlier when that
is the case. This should not cause any visible effects.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20211229165751.3774248-4-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>