arm64: a37xx: Remove DM_I2C_COMPAT from the board config

Remove DM_I2C_COMPAT from the board configurations for
Armada 37xx platform boards for supressing the buid tim
warning.

Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Igal Liberman <igall@marvell.com>
Cc: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Stefan Roese <sr@denx.de>