wifi: rtw89: regd: avoid using BITMAP_FROM_U64() to assign function bitmap

Since there are two function features for now, func_bitmap[] has single
one element, which BITMAP_FROM_U64() generating two elements is exceeded.
Change to assign function bitmap barely.

With i386-allmodconfig (a 32 bit system), it throws

 >> include/linux/bitmap.h:736:33: warning: excess elements in array initializer
      736 |                                 ((unsigned long) ((u64)(n) >> 32))
          |                                 ^
    drivers/net/wireless/realtek/rtw89/regd.c:16:34: note: in expansion of macro 'BITMAP_FROM_U64'
       16 |                 .func_bitmap = { BITMAP_FROM_U64(_fmap), },     \
          |                                  ^~~~~~~~~~~~~~~
    drivers/net/wireless/realtek/rtw89/regd.c:20:9: note: in expansion of macro 'COUNTRY_REGD'
       20 |         COUNTRY_REGD("00", RTW89_WW, RTW89_WW, RTW89_WW, 0x0);
          |         ^~~~~~~~~~~~

Fixes: 79a36fc5 ("wifi: rtw89: regd: handle supported regulatory functions by country")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202502031932.BMQ4lhJT-lkp@intel.com/


Cc: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250205014051.13765-1-pkshih@realtek.com