[DBGHELP][NDK][RTL] *RtlComputeCrc32(): Add 'const' to 2nd parameter (#6973)

and sync SAL2 annotations.

It didn't always warn in the past, our gutfeeling (we have *not* double-checked that thesis!) is that the warnings might have been triggered when 0.4.15-dev-958-g 237aa3a9c13f6e9a3104b4242972382ca7afdc11 was committed

dll/win32/dbghelp/compat.c

···
  * @implemented
  */
 ULONG
-__RtlComputeCrc32(ULONG Initial, PUCHAR Data, ULONG Length)
+__RtlComputeCrc32(ULONG Initial, const UCHAR *Data, ULONG Length)
 {
   ULONG CrcValue = ~Initial;
 

dll/win32/dbghelp/compat.h

···
 PIMAGE_NT_HEADERS __RtlImageNtHeader(void *data);
 PVOID __RtlImageRvaToVa (const IMAGE_NT_HEADERS* NtHeader, PVOID BaseAddress, ULONG Rva, PIMAGE_SECTION_HEADER *SectionHeader);
 PVOID __RtlImageDirectoryEntryToData(PVOID BaseAddress, BOOLEAN MappedAsImage, USHORT Directory, PULONG Size);
-ULONG __RtlComputeCrc32(ULONG Initial, PUCHAR Data, ULONG Length);
+ULONG __RtlComputeCrc32(ULONG Initial, const UCHAR *Data, ULONG Length);
 
 typedef struct _CLIENT_ID
 {

sdk/include/ndk/rtlfuncs.h

···
 NTAPI
 RtlComputeCrc32(
     _In_ ULONG InitialCrc,
-    _In_ PUCHAR Buffer,
+    _In_ const UCHAR *Buffer,
     _In_ ULONG Length
 );
 

sdk/lib/rtl/crc32.c

···
  * @implemented
  */
 ULONG NTAPI
-RtlComputeCrc32(IN ULONG Initial,
-                IN PUCHAR Data,
-                IN ULONG Length)
+RtlComputeCrc32(_In_ ULONG Initial,
+                _In_ const UCHAR *Data,
+                _In_ ULONG Length)
 {
   ULONG CrcValue = ~Initial;