rtw88: fix sparse warnings for DPK

sparse warnings:
    drivers/net/wireless/realtek/rtw88/rtw8822c.c:2871:6: sparse:
sparse: symbol 'rtw8822c_dpk_cal_coef1' was not declared. Should it be
static?
    drivers/net/wireless/realtek/rtw88/rtw8822c.c:3112:6: sparse:
sparse: symbol 'rtw8822c_dpk_track' was not declared. Should it be
static?

Fixes: 5227c2ee ("rtw88: 8822c: add SW DPK support")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>