MdeModulePkg/DxeCorePerfLib: Add status check instead of ASSERT

MdeModulePkg/DxeCorePerfLib: Add status check instead of ASSERT

Currently DxeCorePerformanceLib will get SMM performance data based
on SMM communication handler. If SMM communication handler returns error,
the library will ASSERT. In fact, if SMM perf data is not found.
DXE perf data can still be dumped. So using status check instead of
ASSERT is better.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>