mtd: rawnand: brcmnand: Refactored code to introduce helper functions

mtd: rawnand: brcmnand: Refactored code to introduce helper functions

Refactored NAND ECC and CMD address configuration code to use helper
functions.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
[Ported to U-Boot from the Linux kernel]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Acked-by: William Zhang <william.zhang@broadcom.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>