__page_to_pfn: Fix typo in comment

Fix typo in __page_to_pfn comment: s/encorded/encoded.
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

include/asm-generic/memory_model.h

@@ -53,7 +53,7 @@
 
 #elif defined(CONFIG_SPARSEMEM)
 /*
- * Note: section's mem_map is encorded to reflect its start_pfn.
+ * Note: section's mem_map is encoded to reflect its start_pfn.
  * section[i].section_mem_map == mem_map's address - start_pfn;
  */
 #define __page_to_pfn(pg)					\