nds32: adp-ag102: use 'faraday/ftpci100.h' for pci_ftpci_init

Due to improper external function declaration,
building U-Boot for the adp-ag102 board shows
this warning:

  adp-ag102.c: In function 'pci_init_board':
  adp-ag102.c:95: warning: function declaration isn't a prototype

Include the 'faraday/ftpci100.h' header which
provides the proper declaration and remove the
local declaration to get rid of the warning.

Compile tested only.

Cc: Macpaul Lin <macpaul@andestech.com>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>