Fix misc-macro-parentheses warnings in adb, debuggerd, libbacktrace.

Bug: 28705665
Change-Id: I469b2a882f6d1f399bfc22c75a26da245991fc33
diff --git a/libbacktrace/GetPss.cpp b/libbacktrace/GetPss.cpp
index b4dc48d..6d750ea 100644
--- a/libbacktrace/GetPss.cpp
+++ b/libbacktrace/GetPss.cpp
@@ -24,7 +24,7 @@
 
 // This is an extremely simplified version of libpagemap.
 
-#define _BITS(x, offset, bits) (((x) >> offset) & ((1LL << (bits)) - 1))
+#define _BITS(x, offset, bits) (((x) >> (offset)) & ((1LL << (bits)) - 1))
 
 #define PAGEMAP_PRESENT(x)     (_BITS(x, 63, 1))
 #define PAGEMAP_SWAPPED(x)     (_BITS(x, 62, 1))