kernel-yocto/meta: common-pc: add pci-siov to feature fragments

kernel-yocto/meta: common-pc: add pci-siov to feature fragments

The common-pc ethernet selection has drivers that depend on pci_iov
being defined. As such, we should include that feature fragment
or we get build warnings:

    ---------- CONFIG_BNX2X_SRIOV -----------------
    Config: CONFIG_BNX2X_SRIOV
    From:   work-shared/qemux86-64/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc-eth.cfg
    Requested value:  CONFIG_BNX2X_SRIOV=y
    Actual value:

    Config 'BNX2X_SRIOV' has the following conditionals:
    BNX2X && PCI_IOV (value: "n")
    BNX2X && PCI_IOV (value: "n")
    Dependency values are:
      BNX2X [m] PCI_IOV [n] y [y]

    ---------- CONFIG_BNXT_SRIOV -----------------
    Config: CONFIG_BNXT_SRIOV
    From: work-shared/qemux86-64/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc-eth.cfg
    Requested value:  CONFIG_BNXT_SRIOV=y
    Actual value:

    Config 'BNXT_SRIOV' has the following conditionals:
    BNXT && PCI_IOV (value: "n")
    BNXT && PCI_IOV (value: "n")
    Dependency values are:
      y [y] BNXT [m] PCI_IOV [n]

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>