Use arithmetic type to represent alignments (not in log2) everywhere.

This is the final step of conversion. Now log2 numbers are removed
from everywhere!

llvm-svn: 233246
diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFile.h b/lld/lib/ReaderWriter/MachO/MachONormalizedFile.h
index 449d619..134c28d 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFile.h
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFile.h
@@ -114,7 +114,7 @@
   StringRef       sectionName;
   SectionType     type;
   SectionAttr     attributes;
-  PowerOf2        alignment;
+  uint16_t        alignment;
   Hex64           address;
   ArrayRef<uint8_t> content;
   Relocations     relocations;