MdeModulePkg/Variable: Parameterize VARIABLE_INFO_ENTRY buffer

MdeModulePkg/Variable: Parameterize VARIABLE_INFO_ENTRY buffer

UpdateVariableInfo () currently accepts parameters regarding updates
to be made to a global variable of type VARIABLE_INFO_ENTRY. This
change passes the structure by pointer to UpdateVariableInfo ()
so structures other than the fixed global variable can be updated.

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
Reviewed-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>