Fix spelling mistakes in AMDGPU target comments. NFC.

Identified by Pedro Giffuni in PR27636.

llvm-svn: 287333
diff --git a/llvm/lib/Target/AMDGPU/R600Packetizer.cpp b/llvm/lib/Target/AMDGPU/R600Packetizer.cpp
index c0f08cf..5b6dd1e 100644
--- a/llvm/lib/Target/AMDGPU/R600Packetizer.cpp
+++ b/llvm/lib/Target/AMDGPU/R600Packetizer.cpp
@@ -281,7 +281,7 @@
       return false;
     }
 
-    // We cannot read LDS source registrs from the Trans slot.
+    // We cannot read LDS source registers from the Trans slot.
     if (isTransSlot && TII->readsLDSSrcReg(MI))
       return false;