arm: mx6: Change defines ENET_xxMHz to ENET_xxMHZ (no CamelCase)

arm: mx6: Change defines ENET_xxMHz to ENET_xxMHZ (no CamelCase)

As checkpatch complaines about these camel-case defines, lets change
them to only use upper-case characters.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Jon Nettleton <jon.nettleton@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>