BaseTools: Remove non-ascii character of StructurePcd comment

BaseTools: Remove non-ascii character of StructurePcd comment

Currently, the ConvertFceToStructurePcd.py tool generate
StructurePcd dsc file with comments from UNI file including
non-ascii character. Following DSC spec, there should not have
non-ascii character in DSC file. This patch removes the non-ascii
character when adding the comment and changes the circle R to (R).

Signed-off-by: Yuwei Chen <yuwei.chen@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>