matrix-stack: Fix the _cogl_matrix_entry_equal function
matrix-stack: Fix the _cogl_matrix_entry_equal function

The _cogl_matrix_entry_equal function has a large switch statement to
do the right kind of comparison for the entry. However most of the
entries have a return statement that is only conditionally reached.
There were no corresponding break statements to the case labels so
presumably if the comparison succeeded for the correct entry type it
would also flow through and try the comparison for the next type which
would be extremely unlikely to pass.

Reviewed-by: Robert Bragg <12e9293ec6b30c7fa8a0926af42807e929c1684f@linux.intel.com>

gcampax/cogl,gcampax/cogl,djdeath/cogl,djdeath/cogl,gcampax/cogl,djdeath/cogl-android,gcampax/cogl,djdeath/cogl-android,djdeath/cogl-android,djdeath/cogl