[llvm-mca] Views are now independent from resource masks. NFCI

This change removes method Backend::getProcResourceMasks() and simplifies some
logic in the Views. This effectively removes yet another dependency between the
views and the Backend.
No functional change intended.

llvm-svn: 327214
diff --git a/llvm/tools/llvm-mca/Backend.h b/llvm/tools/llvm-mca/Backend.h
index a000d16..dadab2d 100644
--- a/llvm/tools/llvm-mca/Backend.h
+++ b/llvm/tools/llvm-mca/Backend.h
@@ -70,7 +70,7 @@
             this, MRI, Subtarget.getSchedModel().MicroOpBufferSize,
             RegisterFileSize, MaxRetirePerCycle, DispatchWidth, HWS.get())),
         SM(Source), Cycles(0) {
-    IB = llvm::make_unique<InstrBuilder>(MCII, getProcResourceMasks());
+    IB = llvm::make_unique<InstrBuilder>(MCII, HWS->getProcResourceMasks());
   }
 
   void run() {
@@ -93,9 +93,6 @@
   const llvm::MCSchedModel &getSchedModel() const {
     return STI.getSchedModel();
   }
-  const llvm::ArrayRef<uint64_t> getProcResourceMasks() const {
-    return HWS->getProcResourceMasks();
-  }
 
   double getRThroughput(const InstrDesc &ID) const {
     return HWS->getRThroughput(ID);