maint: avoid 'const fooPtr' in cpu files

'const fooPtr' is the same as 'foo * const' (the pointer won't
change, but it's contents can).  But in general, if an interface
is trying to be const-correct, it should be using 'const foo *'
(the pointer is to data that can't be changed).

Fix up offenders in src/cpu.

* src/cpu/cpu.h (cpuArchDecode, cpuArchEncode, cpuArchUpdate)
(cpuArchHasFeature, cpuDecode, cpuEncode, cpuUpdate)
(cpuHasFeature): Use intended type.
* src/conf/cpu_conf.h (virCPUDefCopyModel, virCPUDefCopy):
Likewise.
(virCPUDefParseXML): Drop const.
* src/cpu/cpu.c (cpuDecode, cpuEncode, cpuUpdate, cpuHasFeature):
Fix fallout.
* src/cpu/cpu_x86.c (x86ModelFromCPU, x86ModelSubtractCPU)
(x86DecodeCPUData, x86EncodePolicy, x86Encode, x86UpdateCustom)
(x86UpdateHostModel, x86Update, x86HasFeature): Likewise.
* src/cpu/cpu_s390.c (s390Decode): Likewise.
* src/cpu/cpu_arm.c (ArmDecode): Likewise.
* src/cpu/cpu_powerpc.c (ppcModelFromCPU, ppcCompute, ppcDecode)
(ppcUpdate): Likewise.
* src/conf/cpu_conf.c (virCPUDefCopyModel, virCPUDefCopy)
(virCPUDefParseXML): Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>

src/cpu/cpu.c

@@ -132,7 +132,7 @@ cpuCompare(virCPUDefPtr host,
 
 int
 cpuDecode(virCPUDefPtr cpu,
-          const virCPUDataPtr data,
+          const virCPUData *data,
           const char **models,
           unsigned int nmodels,
           const char *preferred)
@@ -175,7 +175,7 @@ cpuDecode(virCPUDefPtr cpu,
 
 int
 cpuEncode(virArch arch,
-          const virCPUDefPtr cpu,
+          const virCPUDef *cpu,
           virCPUDataPtr *forced,
           virCPUDataPtr *required,
           virCPUDataPtr *optional,
@@ -402,7 +402,7 @@ cpuBaseline(virCPUDefPtr *cpus,
 
 int
 cpuUpdate(virCPUDefPtr guest,
-          const virCPUDefPtr host)
+          const virCPUDef *host)
 {
     struct cpuArchDriver *driver;
 
@@ -422,7 +422,7 @@ cpuUpdate(virCPUDefPtr guest,
 }
 
 int
-cpuHasFeature(const virCPUDataPtr data,
+cpuHasFeature(const virCPUData *data,
               const char *feature)
 {
     struct cpuArchDriver *driver;