Bluetooth: controller: radio: Fix wrong argument of radio_df_ctrl_set

While RADIO_DFECTRL1_TSAMPLESPACING and RADIO_DFECTRL1_TSAMPLESPACINGREF
has similar values, but they are logically different.
As expected by "radio_df_ctrl_set" function, TSAMPLESPACING should be
passed to this function not TSAMPLESPACINGREF.

Signed-off-by: Saleh Mehdikhani <saleh.mehdikhani@unikie.com>