Platform/ARM/VExpressPkg: Remove non-ASCII characters

The patch at "4be8625a
Platform/ARM/VExpressPkg: Add support for FVP RevC model"
introduced a new file SsdtPci.asl. The file SsdtPci.asl
had a few non-ASCII characters in the code comments.
These resulted in the Trim utility generating a warning
that caused the firmware build to fail on a Linux
development PC.

Therefore, remove the non-ASCII characters as it results
in builds failures on a Linux development PC.

Note: This issue was not observed on a Windows development
PC.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Thomas Abraham <thomas.abraham@arm.com>