lantiq: fix eeprom driver build warnings:

lantiq: fix eeprom driver build warnings:

This patch fixes the following build warnings:

arch/mips/lantiq/xway/ath5k_eep.c:34:12: error: no previous prototype for 'of_ath5k_eeprom_probe' [-Werror=missing-prototypes]
   34 | int __init of_ath5k_eeprom_probe(struct platform_device *pdev)
      |            ^~~~~~~~~~~~~~~~~~~~~
arch/mips/lantiq/xway/eth_mac.c:15:11: error: no previous prototype for 'ltq_get_eth_mac' [-Werror=missing-prototypes]
   15 | const u8* ltq_get_eth_mac(void)
      |           ^~~~~~~~~~~~~~~

Signed-off-by: Shiji Yang <[email protected]>