drivers: clock_control: gd32: Correcting timer node detection

DT_COMPAT_GET_ANY_STATUS_OKAY is not suited for the node's existing check.
(This macro returns the stem of the DTS macro name,
 the stem part is not a defined symbol.)
Instead, it should use the DT_HAS_COMPAT_STATUS_OKAY macro.

Signed-off-by: TOKITA Hiroshi <tokita.hiroshi@gmail.com>