target-ppc: disable unsupported modes for SPR_CTRL/SPR_UCTRL

The Figure 17 "SPR encodings" of the PowerISA 2.07 describes CTRL SPR as:

                       priviledged
#   spr5-9 spr0-4 name mtspr mfspr len cat
136 00100  01000  CTRL   -    no    32  S
152 00100  11000  CTRL  yes    -    32  S

According to this chart, the hypervisor's CTRL (#152) does not support
reading, the user-space's CTRL (UCTRL, #136) does not support writing.

This replaces unsupported operations with the default SPR_NOACCESS hook.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>

target-ppc/translate_init.c

@@ -6739,11 +6739,11 @@ static void init_proc_970FX (CPUPPCState *env)
                  0x00000000);
     spr_register(env, SPR_CTRL, "SPR_CTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x00000000);
     spr_register(env, SPR_UCTRL, "SPR_UCTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x00000000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,
@@ -6909,11 +6909,11 @@ static void init_proc_power5plus(CPUPPCState *env)
                  0x00000000);
     spr_register(env, SPR_CTRL, "SPR_CTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x00000000);
     spr_register(env, SPR_UCTRL, "SPR_UCTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x00000000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,
@@ -7014,11 +7014,11 @@ static void init_proc_POWER7 (CPUPPCState *env)
     /* XXX : not implemented */
     spr_register(env, SPR_CTRL, "SPR_CTRLT",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x80800000);
     spr_register(env, SPR_UCTRL, "SPR_CTRLF",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x80800000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,