powerpc/papr_scm: Mark papr_scm_ndctl() as static

Function papr_scm_ndctl() is neither exported from the module nor
called directly from outside 'papr.c' hence should be marked 'static'.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200130040206.79998-1-vaibhav@linux.ibm.com

arch/powerpc/platforms/pseries/papr_scm.c

@@ -246,8 +246,9 @@ static int papr_scm_meta_set(struct papr_scm_priv *p,
 	return 0;
 }
 
-int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
-		unsigned int cmd, void *buf, unsigned int buf_len, int *cmd_rc)
+static int papr_scm_ndctl(struct nvdimm_bus_descriptor *nd_desc,
+			  struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+			  unsigned int buf_len, int *cmd_rc)
 {
 	struct nd_cmd_get_config_size *get_size_hdr;
 	struct papr_scm_priv *p;