crypto: mediatek - remove redundant clock setting

This patch removes redundant clock setting for 'clk_ethif', which is
the parent of 'clk_cryp'. Hence, we just need to handle its child.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>