HidlCache: Minor code readability change

The locked() method returns a bool, so we change the check of it
to a boolean check, instead of an integral comparison.

This should have no behavioral change, as the integral comparison
was equivalent to this boolean one.  But the code should be a
little clearer to read.

Test: Treehugger
Change-Id: I05ab025cf4d87e2499f2c96fb265eb207294d61a
1 file changed