armv8: fsl-layerscape: spl: fix build error when DM_I2C is enabled

Fix below SPL build error when DM_I2C is enabled,
- arch/arm/cpu/armv8/built-in.o: In function `board_init_f:
  arch/arm/cpu/armv8/fsl-layerscape/spl.c:74: undefined reference to `i2c_init_all'
  arch/arm/cpu/armv8/fsl-layerscape/spl.c:74:(.text.board_init_f+0x30):
  relocation truncated to fit: R_AARCH64_CALL26 against undefined symbol
  `i2c_init_all'
  make[2]: *** [spl/u-boot-spl] Error 1
  make[1]: *** [spl/u-boot-spl] Error 2
  make: *** [sub-make] Error 2
  arch/arm/cpu/armv8/fsl-layerscape/spl.c: In function 'board_init_f':
  arch/arm/cpu/armv8/fsl-layerscape/spl.c:74:2: warning: implicit
  declaration of function 'i2c_init_all'; did you mean 'misc_init_r'?
  [-Wimplicit-function-declaration]`

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>