dpll: fix dpll_xa_ref_*_del() for multiple registrations

In the Linux kernel, the following vulnerability has been resolved:

dpll: fix dpll_xa_ref_*_del() for multiple registrations

Currently, if there are multiple registrations of the same pin on the

same dpll device, following warnings are observed:

WARNING: CPU: 5 PID: 2212 at drivers/dpll/dpll_core.c:143 dpll_xa_ref_pin_del.isra.0+0x21e/0x230

WARNING: CPU: 5 PID: 2212 at drivers/dpll/dpll_core.c:223 __dpll_pin_unregister+0x2b3/0x2c0

The problem is, that in both dpll_xa_ref_dpll_del() and

dpll_xa_ref_pin_del() registration is only removed from list in case the

reference count drops to zero. That is wrong, the registration has to

be removed always.

To fix this, remove the registration from the list and free

it unconditionally, instead of doing it only when the ref reference

counter reaches zero.