ramoops: use persistent_ram_free() instead of kfree() for freeing prz

persistent_ram_zone(=prz) structures are allocated by persistent_ram_new(),
which includes vmap() or ioremap(). But they are currently freed by
kfree(). This uses persistent_ram_free() for correct this asymmetry usage.
Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.kw@hitachi.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Seiji Aguchi <seiji.aguchi.tr@hitachi.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

fs/pstore/ram.c

@@ -643,11 +643,11 @@ static int ramoops_probe(struct platform_device *pdev)
 	kfree(cxt->pstore.buf);
 fail_clear:
 	cxt->pstore.bufsize = 0;
-	kfree(cxt->mprz);
+	persistent_ram_free(cxt->mprz);
 fail_init_mprz:
-	kfree(cxt->fprz);
+	persistent_ram_free(cxt->fprz);
 fail_init_fprz:
-	kfree(cxt->cprz);
+	persistent_ram_free(cxt->cprz);
 fail_init_cprz:
 	ramoops_free_przs(cxt);
 fail_out: