Fix typo in function name PxeBcFlushStaionIp which should be PxeBcFlushStationIp.

Fix typo in function name PxeBcFlushStaionIp which should be PxeBcFlushStationIp.
Signed-off-by: Mauro Faccenda <faccenda@gmail.com>
Reviewed-by: Ye, Ting <ting.ye@intel.com>
Reviewed-by: Fu, Siyuan <siyuan.fu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15480 6f19259b-4bc3-4df7-8a09-765794883524