PCI/ASPM: Remove unnecessary ASPM_STATE_L1SS check

Previously aspm_l1ss_init() checked if ASPM_STATE_L1SS is supported before
calling aspm_calc_l12_info(), only for that function to return if
ASPM_STATE_L1_2_MASK is not supported. Simplify the logic by directly
checking for ASPM_STATE_L1_2_MASK.

Link: https://lore.kernel.org/r/20230504111301.229358-6-ajayagarwal@google.com


Signed-off-by: Ajay Agarwal <ajayagarwal@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>