Fix translation for 64-bit builds

* src/util/w32-util.h (GPG4WIN_REGKEY_2): Remove.
(GPG4WIN_REGKEY_3): Use same value for 32-bit and 64-bit.

GPG4WIN_REGKEY_2 is not used anymore. And we need to use the normal
registry path also for 64-bit builds. The code that reads registry
values automatically reads the alternative registry path as fallback
if necessary.

This fixes the problem that gpg4win-tools didn't find the translations
of gpgol because it always looked under Software\\Wow6432Node\\Gpg4win
for "Install Directory".

• GnuPG-bug-id: T7835