target/m68k: Fix exception frame format for 68010

target/m68k: Fix exception frame format for 68010

From the 68010 a word with the frame format and exception vector
are placed on the stack before the PC and SR.

M68K_FEATURE_QUAD_MULDIV is currently checked to workout if to do
this or not for the configured CPU but that flag isn't set for
68010 so currently the exception stack when 68010 is configured
is incorrect.

It seems like checking M68K_FEATURE_MOVEFROMSR_PRIV would do but
adding a new flag that shows exactly what is going on here is
maybe clearer.

Add a new flag for the behaviour, M68K_FEATURE_EXCEPTION_FORMAT_VEC,
and set it for 68010 and above, and then use it to control if the
format and vector word are pushed/pop during exception entry/exit.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2164
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Message-ID: <20240115101643.2165387-1-daniel@0x0f.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>