FatPkg/FatPei: Remove extraneous debug message argument

FatPkg/FatPei: Remove extraneous debug message argument

This debug macro should take one argument based on the number of
print specifiers defined. However, two arguments are given.

It looks like the code may have been refactored such that the
second argument was moved to a new print and this argument was
not removed. In any case, it should not be there now.

Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>