phy: cadence-torrent: Remove use of CamelCase to fix checkpatch CHECK message

Script checkpatch with --strict option gives message:
CHECK: Avoid CamelCase: <REF_CLK_19_2MHz>
CHECK: Avoid CamelCase: <REF_CLK_25MHz>
Fix this by removing CamelCase usage. No functional change.

Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>
Link: https://lore.kernel.org/r/20210728145454.15945-2-sjakhade@cadence.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>