rtw88: fix GENMASK_ULL for u64

rtw88: fix GENMASK_ULL for u64

This fixes compile warning:

    In file included from include/linux/bitops.h:5:0,
                     from include/linux/kernel.h:12,
                     from include/asm-generic/bug.h:19,
                     from arch/mips/include/asm/bug.h:42,
                     from include/linux/bug.h:5,
                     from include/net/mac80211.h:16,
                     from drivers/net/wireless/realtek/rtw88/main.h:8,
                     from drivers/net/wireless/realtek/rtw88/main.c:5:
    drivers/net/wireless/realtek/rtw88/main.c: In function 'rtw_update_rate_mask':
      include/linux/bits.h:23:11: warning: right shift count is negative
      [-Wshift-count-negative]
       (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
               ^
    drivers/net/wireless/realtek/rtw88/main.c:622:17: note: in expansion of macro 'GENMASK'
      u64 cfg_mask = GENMASK(63, 0);
                     ^~~~~~~

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: f39e9bd49a3d ("rtw88: add set_bitrate_mask support")
Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>