net: stmmac: Fix clock handling on remove path

While unloading the dwmac-intel driver, clk_disable_unprepare() is
being called twice in stmmac_dvr_remove() and
intel_eth_pci_remove(). This causes kernel panic on the second call.

Removing the second call of clk_disable_unprepare() in
intel_eth_pci_remove().

Fixes: 09f012e64e4b ("stmmac: intel: Fix clock handling on error and remove paths")
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>