input: synaptics_i2c_rmi4: Reinitialize list after freeing it

During firmware update and device reset through sysfs, query info
needs to be updated in support_fn_list. However, both these procedures
free the existing list before updation without setting its list head
to consistent state. Reinitialize the list head of support_fn_list
to avoid memory fault during updation.

CRs-Fixed: 589295
Change-Id: I560e2df53d258e273ff9890c7c62b90a58a423f7
Signed-off-by: c_sgarna <c_sgarna@codeaurora.org>