Fixed typos: hanlder should be handler.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15642 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/Network/SnpDxe/Snp.c

@@ -26,7 +26,7 @@ V2P                         *mV2p = NULL; // undi3.0 map_list head
   One notified function to stop UNDI device when gBS->ExitBootServices() called.
 
   @param  Event                   Pointer to this event
-  @param  Context                 Event hanlder private data
+  @param  Context                 Event handler private data
 
 **/
 VOID