MdeModulePkg RegularExpressionDxe: Add the missing EFIAPI for the function

The function with the variable parameters should have EFIAPI.

Cc: Feng Tian <feng.tian@intel.com>
Cc: Cinnamon Shia <cinnamon.shia@hpe.com>
Cc: Cecil Sheng <cecil.sheng@hpe.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

MdeModulePkg/Universal/RegularExpressionDxe/Oniguruma/OnigurumaUefiPort.h

@@ -69,7 +69,7 @@ typedef UINTN size_t;
 
 int OnigStrCmp (char* Str1, char* Str2);
 
-int sprintf_s (char *str, size_t sizeOfBuffer, char const *fmt, ...);
+int EFIAPI sprintf_s (char *str, size_t sizeOfBuffer, char const *fmt, ...);
 
 #define exit(n) ASSERT(FALSE);