ShellPkg: stop taking EFI_HANDLE in place of SHELL_FILE_HANDLE

ShellPkg: stop taking EFI_HANDLE in place of SHELL_FILE_HANDLE

The TouchFileByHandle() and IsDirectoryEmpty() functions are passed
SHELL_FILE_HANDLE parameters, and they use those parameters correctly.
However, their parameter lists say EFI_HANDLE.

Spell out the right type in the parameter lists.

In practice, this change is a no-op (because, quite regrettably, both
EFI_HANDLE and SHELL_FILE_HANDLE are specified to be typedefs of (VOID*)).

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Zhichao Gao <zhichao.gao@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>