rcar_gen3: drivers: ddr: Replace BITn with BIT(n) macro

Remove the ad-hoc BITn macros and replace them with generic BIT(n) macro.
No functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: I5d0b44d6cba5a69895fed505f6ff780d3574907f
8 files changed