[iscsiboot] Inhibit harmless warning on 64-bit builds

For amd64 builds, the compiler complains with the message

  warning C4327: '=' : indirection alignment of LHS (2) is greater than RHS (1)

As far as I am aware, x64_64 is perfectly capable of accessing
unaligned 16-bit quantities, so I think this is safe to inhibit.

driver/iscsiboot.c

@@ -18,6 +18,7 @@
 
 #pragma warning(disable:4201)  /* nameless struct/union warning */
 #pragma warning(disable:4214)  /* non-int bitfield warning */
+#pragma warning(disable:4327)  /* indirection alignment mismatch */
 
 #include <ntddk.h>
 #include <ntstrsafe.h>