stmmac: intel: Fix kernel panic on pci probe

stmmac: intel: Fix kernel panic on pci probe

The commit "stmmac: intel: Adding ref clock 1us tic for LPI cntr"
introduced a regression which leads to the kernel panic duing loading
of the dwmac_intel module.

Move the code block after pci resources is obtained.

Fixes: b4c5f83ae3f3 ("stmmac: intel: Adding ref clock 1us tic for LPI cntr")
Cc: Voon Weifeng <weifeng.voon@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@intel.com>
Link: https://lore.kernel.org/r/20201029093228.1741-1-vee.khee.wong@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>