BaseTools:Make BaseTools support new rules to generate RAW FFS FILE

BaseTools:Make BaseTools support new rules to generate RAW FFS FILE

BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=1765

If RAW FFS File Rule has no section for its data.For RAW FFS File,
directly call GenFfs tool to generate FFS file.

Ffs Rule:
[Rule.Common.USER_DEFINED.MicroCode]
  FILE RAW = $(NAMED_GUID) {
        $(INF_OUTPUT)/$(MODULE_NAME).bin
  }
[Rule.Common.USER_DEFINED.LOGO]
  FILE RAW = $(NAMED_GUID) {
                       |.bmp
  }

As shown in the rule above,if SectionType and FileType not defined,
FFS files are generated directly, and no other type of file is
generated.

The patch is to make the BaseTools support these two rules

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>