powerpc/secvar: Clean up init error messages

Remove unnecessary prefixes from error messages in secvar_sysfs_init()
(the file defines pr_fmt, so putting "secvar:" in every message is
unnecessary). Make capitalisation and punctuation more consistent.

Signed-off-by: Andrew Donnellan <[e-mail]>
Signed-off-by: Russell Currey <[e-mail]>
Reviewed-by: Stefan Berger <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/kernel/secvar-sysfs.c

···
 	int rc;
 
 	if (!secvar_ops) {
-		pr_warn("secvar: failed to retrieve secvar operations.\n");
+		pr_warn("Failed to retrieve secvar operations\n");
 		return -ENODEV;
 	}
 
 	secvar_kobj = kobject_create_and_add("secvar", firmware_kobj);
 	if (!secvar_kobj) {
-		pr_err("secvar: Failed to create firmware kobj\n");
+		pr_err("Failed to create firmware kobj\n");
 		return -ENOMEM;
 	}
 
···
 
 	secvar_kset = kset_create_and_add("vars", NULL, secvar_kobj);
 	if (!secvar_kset) {
-		pr_err("secvar: sysfs kobject registration failed.\n");
+		pr_err("sysfs kobject registration failed\n");
 		kobject_put(secvar_kobj);
 		return -ENOMEM;
 	}