msm: kgsl: Fix profiler group id comparison

Not all groups have names all the time.  Do the right things when
the group id doesn't have a name.  Also make sure the strings are
actually equal in length to avoid subset group names like vbif and
vbif_pwr.

Change-Id: I68c9db519e46e962120856fdff1d1c46de55ca70
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>