devel/llvm17: remove obsolete powerpc patch

The lines immediatly below the inserted code do the same thing with
more elegance.

Technically this changes the package contents, but there is no
functional change so don't make everyone build with a PORTREVSION bump.
We'll do that soon enough when 17.0.3 comes out.

Reported by:	Brad Smith <brad@comstyle.com>

devel/llvm17/files/patch-lib_Target_PowerPC_PPCTargetMachine.cpp

@@ -1,23 +0,0 @@
---- llvm/lib/Target/PowerPC/PPCTargetMachine.cpp.orig	2019-07-04 07:43:51 UTC
-+++ llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
-@@ -209,6 +209,20 @@ static PPCTargetMachine::PPCABI computeTargetABI(const
-   if (TT.isMacOSX())
-     return PPCTargetMachine::PPC_ABI_UNKNOWN;
- 
-+  if (TT.isOSFreeBSD()) {
-+    switch (TT.getArch()) {
-+    case Triple::ppc64le:
-+    case Triple::ppc64:
-+      if (TT.getOSMajorVersion() >= 13)
-+        return PPCTargetMachine::PPC_ABI_ELFv2;
-+      else
-+        return PPCTargetMachine::PPC_ABI_ELFv1;
-+    case Triple::ppc:
-+    default:
-+      return PPCTargetMachine::PPC_ABI_UNKNOWN;
-+    }
-+  }
-+
-   switch (TT.getArch()) {
-   case Triple::ppc64le:
-     return PPCTargetMachine::PPC_ABI_ELFv2;