ixgbe: Remove unused function declarations

ixgbe: Remove unused function declarations

Commit dc166e22ede5 ("ixgbe: DCB remove ixgbe_fcoe_getapp routine")
leave ixgbe_fcoe_getapp() unused.
Commit ffed21bcee7a ("ixgbe: Don't bother clearing buffer memory for descriptor rings")
leave ixgbe_unmap_and_free_tx_resource() declaration unused.
And commit 3b3bf3b92b31 ("ixgbe: remove unused fcoe.tc field and fcoe_setapp()")
removed the ixgbe_fcoe_setapp() implementation.

Commit c44ade9ef8ff ("ixgbe: update to latest common code module")
declared but never implemented ixgbe_init_ops_generic().

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20230804125203.30924-1-yuehaibing@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>