MdeModulePkg/DxeCapsuleLibFmp: pass progress callback only if it works

MdeModulePkg/DxeCapsuleLibFmp: pass progress callback only if it works

If the first call to UpdateImageProgress() fails, there is no point
in passing a pointer to it to Fmp->SetImage(), since it is highly
unlikely to succeed on any subsequent calls.

This permits the FMP implementation to fall back to an alternate means
of providing feedback to the user, e.g., via the console.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Star Zeng <star.zeng@intel.com>