EmbeddedPkg/CoherentDmaLib: Add missing checks to DmaMap

UEFI Sct validates Dma mapping. For CoherentDmaLib it always failed
because there were no required checks present in DmaMap.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

EmbeddedPkg/Library/CoherentDmaLib/CoherentDmaLib.c

@@ -58,6 +58,12 @@ DmaMap (
   OUT    VOID                           **Mapping
   )
 {
+  if (HostAddress == NULL ||
+      NumberOfBytes == NULL ||
+      DeviceAddress == NULL ||
+      Mapping == NULL ) {
+    return EFI_INVALID_PARAMETER;
+  }
   *DeviceAddress = HostToDeviceAddress (HostAddress);
   *Mapping = NULL;
   return EFI_SUCCESS;