PCI ASPM: cleanup clkpm state in struct pcie_link_state

The "clk_pm_capable", "clk_pm_enable" and "bios_clk_state" fields in
the struct pcie_link_state only take 1-bit value. So those fields
don't need to be defined as unsigned int. This patch makes those
fields 1-bit, and cleans up some related code.

Acked-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>