sfc: Remove falcon deadcode

sfc: Remove falcon deadcode

ef4_farch_dimension_resources(), ef4_nic_fix_nodesc_drop_stat(),
ef4_ticks_to_usecs() and ef4_tx_get_copy_buffer_limited() were
copied over from efx_ equivalents in 2016 but never used by
commit 5a6681e22c14 ("sfc: separate out SFC4000 ("Falcon") support into new
sfc-falcon driver")

EF4_MAX_FLUSH_TIME is also unused.

Remove them.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Acked-by: Martin Habets <habetsm.xilinx@gmail.com>
Link: https://patch.msgid.link/20241102151625.39535-2-linux@treblig.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>