msm: synx: fix synx handle/s mapping to synx object

Multiple synx integer handles can me mapped to the same synx object
metadata (synx_table_row) due to sharing across processes. However,
the synx metadata has memory to save only single handle.
This results in failure to clean all the handles mapped to the synx
obj during clean up resulting in exhaustion of available handles for
future uses.
Change fixes this issue by saving the mapped synx handles in a list
and iterates the list to remove the hanldes during clean up.

Change-Id: Ia1aa791743f63dfd79804f235edd379623896727
Signed-off-by: Sumukh Hallymysore Ravindra <shallymy@codeaurora.org>