The VaListToBaseList function in PeiDebugLibDebugPpi/DebugLib.c does not
recognize the comma (`,`) flag in printf-style format strings. When a
driver uses format strings with thousand separators like "%,ld" to format
large numbers (e.g., 1234567 as "1,234,567"), the VaListToBaseList parser
fails to recognize the comma flag and causes incorrect argument extraction
from the VA_LIST, leading to unexpected or corrupted debug output.
The change is to add a check for the comma character in the format string
parsing logic to align with BasePrintLib's format parsing logic,
ensuring consistent behavior across all print library implementations.
Signed-off-by: Ray Ni <ray.ni@intel.com>