MdeModulePkg/RamDiskDxe: Use BaseLib linked list iteration macros

MdeModulePkg/RamDiskDxe: Use BaseLib linked list iteration macros

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1959

Replaces usage of the linked list iteration macros defined in RamDiskImpl.h
with the common definition in BaseLib.h.

Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Bret Barkelew <bret.barkelew@microsoft.com>