IntelFrameworkModulePkg Ps2KeyboardDxe: Remove a redundant function

The redundant function DisableKeyboard which is never called
has been removed.
https://bugzilla.tianocore.org/show_bug.cgi?id=1063

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: shenglei <shenglei.zhang@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

IntelFrameworkModulePkg/Bus/Isa/Ps2KeyboardDxe/Ps2Keyboard.h

@@ -299,18 +299,7 @@ InitKeyboard (
   IN BOOLEAN                     ExtendedVerification
   );
 
-/**
-  Disable the keyboard interface of the 8042 controller.
 
-  @param ConsoleIn   - the device instance
-
-  @return status of issuing disable command
-
-**/
-EFI_STATUS
-DisableKeyboard (
-  IN KEYBOARD_CONSOLE_IN_DEV *ConsoleIn
-  );
 
 /**
   Timer event handler: read a series of scancodes from 8042