FindMatlab: Do not query host processor for registry view

`matlab_extract_all_installed_versions_from_registry` searched for
32-bit installations on 32-bit Windows even if win64 was set to 'TRUE'.
Now, no installation will be found if win64 is set to 'TRUE' on 32-bit
Windows, which is also the documented behavior.

Modules/FindMatlab.cmake

@@ -465,7 +465,7 @@ function(matlab_extract_all_installed_versions_from_registry win64 matlab_versio
     message(FATAL_ERROR "[MATLAB] This function can only be called by a Windows host")
   endif()
 
-  if(${win64} AND CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "64")
+  if(${win64})
     set(_view "64")
   else()
     set(_view "32")