Noticed missing include as a build failure on gcc-11:
```
[ 26%] Building CXX object Source/Core/DiscIO/CMakeFiles/discio.dir/WIACompression.cpp.o
../../../../Source/Core/DiscIO/WIACompression.cpp: In lambda function:
../../../../Source/Core/DiscIO/WIACompression.cpp:170:31: error: 'numeric_limits' is not a member of 'std'
170 | std::min<size_t>(std::numeric_limits<unsigned int>().max(), x));
| ^~~~~~~~~~~~~~
../../../../Source/Core/DiscIO/WIACompression.cpp:170:46: error: expected primary-expression before 'unsigned'
170 | std::min<size_t>(std::numeric_limits<unsigned int>().max(), x));
| ^~~~~~~~
```
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>