[lldb] Define LLDB_VERSION_PATCH correctly

In commit ccf1469a lldb got its own generated Version.inc file, with
`LLDB_VERSION` macros. However, it used `LLDB_VERSION_PATCHLEVEL`
instead of the actually correct `LLDB_VERSION_PATCH`. Correct this.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D124672