net: txgbe: fix clk_name exceed MAX_DEV_ID limits

txgbe register clk which name is i2c_designware.pci_dev_id(),
clk_name will be stored in clk_lookup_alloc. If PCIe bus number
is larger than 0x39, clk_name size will be larger than 20 bytes.
It exceeds clk_lookup_alloc MAX_DEV_ID limits. So the driver
shortened clk_name.

Fixes: b63f2048

 ("net: txgbe: Register fixed rate clock")
Signed-off-by: Duanqiang Wen <duanqiangwen@net-swift.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Link: https://lore.kernel.org/r/20240313080634.459523-1-duanqiangwen@net-swift.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>