kernel: igc: Reinstate IGC_REMOVED logic and implement it properly

In the Linux kernel, the following vulnerability has been resolved: igc: Reinstate IGCREMOVED logic and implement it properly The initially merged version of the igc driver code via commit 146740f9abc4, "igc: Add support for PF" contained the following IGCREMOVED checks in the igcrd32/wr32 MMIO...