MdeModulePkg: FaultTolerantWriteDxe: clean up some "success" messages

MdeModulePkg: FaultTolerantWriteDxe: clean up some "success" messages

The "success" messages in FtwRestart(), FtwAbort(), and FtwGetLastWrite()
should be logged on EFI_D_INFO level. We can also unify their format with
the __FUNCTION__ macro.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Drew Jones <drjones@redhat.com>
Suggested-by: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18620 6f19259b-4bc3-4df7-8a09-765794883524