cxgb4: Properly revert VPD changes

cxgb4: Properly revert VPD changes

Clang warns:

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2785:2: error: variable 'kw_offset' is uninitialized when used here [-Werror,-Wuninitialized]
        FIND_VPD_KW(i, "RV");
        ^~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2776:39: note: expanded from macro 'FIND_VPD_KW'
        var = pci_vpd_find_info_keyword(vpd, kw_offset, vpdr_len, name); \
                                             ^~~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2748:34: note: initialize the variable 'kw_offset' to silence this warning
        unsigned int vpdr_len, kw_offset, id_len;
                                        ^
                                         = 0
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2785:2: error: variable 'vpdr_len' is uninitialized when used here [-Werror,-Wuninitialized]
        FIND_VPD_KW(i, "RV");
        ^~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2776:50: note: expanded from macro 'FIND_VPD_KW'
        var = pci_vpd_find_info_keyword(vpd, kw_offset, vpdr_len, name); \
                                                        ^~~~~~~~
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2748:23: note: initialize the variable 'vpdr_len' to silence this warning
        unsigned int vpdr_len, kw_offset, id_len;
                             ^
                              = 0
2 errors generated.

The series "PCI/VPD: Convert more users to the new VPD API functions"
was applied to net-next when it should have been applied to the PCI tree
because of build errors. However, commit d1092f1ca089 ("Revert "Revert
"cxgb4: Search VPD with pci_vpd_find_ro_info_keyword()""") reapplied a
change, resulting in the warning above.

Properly revert commit df9f692ad099 ("cxgb4: Search VPD with
pci_vpd_find_ro_info_keyword()") to fix the warning and restore proper
functionality. This also reverts commit e8618aa5404a ("cxgb4: Remove
unused vpd_param member ec") to avoid future merge conflicts, as that
change has been applied to the PCI tree.

Link: https://lore.kernel.org/r/20210823120929.7c6f7a4f@canb.auug.org.au/
Link: https://lore.kernel.org/r/1ca29408-7bc7-4da5-59c7-87893c9e0442@gmail.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>