Look up source using & instead of equality

Source for an input device may be composite. On some devices, the source
is specified as TOUCHSCREEN | STYLUS. That means a regular lookup of a
MotionRange using just SOURCE_TOUCHSCREEN fails.

Update the code to allow composite sources.

Also, improve the source dump by printing words instead of numbers.

Bug: 198472780
Test: adb shell dumpsys input
Change-Id: I8d395f2bb5a6db031e5c2aa6c1f5152ff067a2bb