libbinder Parcel: compareData const.

This API should probably be removed because it's a derivative API,
but it also does not modify the Parcel, so quick fix.

Bugs: me
Test: build
Change-Id: I4732360f8cbd53491520dd2cb028c13279995dab

Author: Steven Moreland

libs/binder/Parcel.cpp

@@ -683,7 +683,7 @@ status_t Parcel::appendFrom(const Parcel* parcel, size_t offset, size_t len) {
     return err;
 }
 
-int Parcel::compareData(const Parcel& other) {
+int Parcel::compareData(const Parcel& other) const {
     size_t size = dataSize();
     if (size != other.dataSize()) {
         return size < other.dataSize() ? -1 : 1;

libs/binder/include/binder/Parcel.h

@@ -92,7 +92,7 @@ class Parcel {
 
     LIBBINDER_EXPORTED status_t appendFrom(const Parcel* parcel, size_t start, size_t len);
 
-    LIBBINDER_EXPORTED int compareData(const Parcel& other);
+    LIBBINDER_EXPORTED int compareData(const Parcel& other) const;
     LIBBINDER_EXPORTED status_t compareDataInRange(size_t thisOffset, const Parcel& other,
                                                    size_t otherOffset, size_t length,
                                                    int* result) const;