ACPI: fix NULL check in drivers/acpi/osl.c

Spotted by the Coverity checker.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLen Brown <len.brown@intel.com>

drivers/acpi/osl.c

@@ -1032,7 +1032,7 @@ acpi_status
 acpi_os_create_cache(char *name, u16 size, u16 depth, acpi_cache_t ** cache)
 {
 	*cache = kmem_cache_create(name, size, 0, 0, NULL, NULL);
-	if (cache == NULL)
+	if (*cache == NULL)
 		return AE_ERROR;
 	else
 		return AE_OK;