MdeModulePkg/Graphics: Fix spelling mistakes

MdeModulePkg/Graphics: Fix spelling mistakes

Fix various spelling mistakes in GraphicsConsoleDxe, ConsPlitter,
and SimpleTextOut header

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Ard Biesheuvel <Ard.Biesheuvel@arm.com>
Cc: Pete Batard <pete@akeo.ie>
Signed-off-by: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>