target/ppc: pass const string to kvmppc_is_mem_backend_page_size_ok()

This function has three implementations. Two are stubs that do nothing
and the third one only passes the obj_path argument to:

Object *object_resolve_path(const char *path, bool *ambiguous);

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target/ppc/kvm.c

@@ -478,7 +478,7 @@ static void kvm_fixup_page_sizes(PowerPCCPU *cpu)
     }
 }
 
-bool kvmppc_is_mem_backend_page_size_ok(char *obj_path)
+bool kvmppc_is_mem_backend_page_size_ok(const char *obj_path)
 {
     Object *mem_obj = object_resolve_path(obj_path, NULL);
     char *mempath = object_property_get_str(mem_obj, "mem-path", NULL);
@@ -499,7 +499,7 @@ static inline void kvm_fixup_page_sizes(PowerPCCPU *cpu)
 {
 }
 
-bool kvmppc_is_mem_backend_page_size_ok(char *obj_path)
+bool kvmppc_is_mem_backend_page_size_ok(const char *obj_path)
 {
     return true;
 }

target/ppc/kvm_ppc.h

@@ -64,7 +64,7 @@ int kvmppc_enable_hwrng(void);
 int kvmppc_put_books_sregs(PowerPCCPU *cpu);
 PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void);
 
-bool kvmppc_is_mem_backend_page_size_ok(char *obj_path);
+bool kvmppc_is_mem_backend_page_size_ok(const char *obj_path);
 
 #else
 
@@ -211,7 +211,7 @@ static inline uint64_t kvmppc_rma_size(uint64_t current_size,
     return ram_size;
 }
 
-static inline bool kvmppc_is_mem_backend_page_size_ok(char *obj_path)
+static inline bool kvmppc_is_mem_backend_page_size_ok(const char *obj_path)
 {
     return true;
 }