ShellPkg: acpiview: Allow passing buffer length to DumpGasStruct()

Modify the signature of the DumpGasStruct() function to include the
buffer length parameter and to return the number of bytes parsed by
the function.

This way it becomes possible to prevent buffer overruns when dumping
Generic Address Structure's (GAS) fields in the acpiview table
parsers.

Update all existing DumpGasStruct() calls in acpiview to add the
length argument.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Zhichao Gao <zhichao.gao@intel.com>

ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c

@@ -134,7 +134,7 @@ DumpDbgDeviceInfo (
   AddrSize = (UINT32*)(Ptr + (*AddrSizeOffset));
   while (Index < (*GasCount)) {
     PrintFieldName (4, L"BaseAddressRegister");
-    DumpGasStruct (DataPtr, 4);
+    DumpGasStruct (DataPtr, 4, GAS_LENGTH);
     PrintFieldName (4, L"Address Size");
     Print (L"0x%x\n", AddrSize[Index]);
     DataPtr += GAS_LENGTH;