target-ppc: Make UCTRL a mirror of CTRL

This changes UCTRL SPR to read from its supermode copy.

This enables reading from UCTRL in user mode.
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: NTom Musta <tommusta@gmail.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

target-ppc/translate_init.c

@@ -7308,8 +7308,8 @@ static void gen_spr_book3s_common(CPUPPCState *env)
                  SPR_NOACCESS, &spr_write_generic,
                  0x00000000);
     spr_register(env, SPR_UCTRL, "SPR_UCTRL",
-                 SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, SPR_NOACCESS,
+                 &spr_read_ureg, SPR_NOACCESS,
+                 &spr_read_ureg, SPR_NOACCESS,
                  0x00000000);
 }