RFR: 8253565: PPC: Remove duplicated if condition in vm_version_ppc.cpp

[Ziviani]

This is a very small change. There're two `if (UseRTMLocking) {` conditions, one just after the other. This code simply
merge them.

https://bugs.openjdk.java.net/browse/JDK-8253565

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Commit messages:
 - 8253565: Remove duplicated if condition in vm_version_ppc.cpp

Changes: https://git.openjdk.java.net/jdk/pull/338/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=338&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253565
  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/338.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/338/head:pull/338

PR: https://git.openjdk.java.net/jdk/pull/338