PCI: aardvark: Fix reading PCI_EXP_RTSTA_PME bit on emulated bridge

PCI: aardvark: Fix reading PCI_EXP_RTSTA_PME bit on emulated bridge

BugLink: https://bugs.launchpad.net/bugs/1969110
[ Upstream commit 735f5ae49e1b44742cc63ca9b5c1ffde3e94ba91 ]

The emulated bridge returns incorrect value for PCI_EXP_RTSTA register
during readout in advk_pci_bridge_emul_pcie_conf_read() function: the
correct bit is BIT(16), but we are setting BIT(23), because the code
does
  *value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16
where
  PCIE_MSG_PM_PME_MASK
is
  BIT(7).

The code should probably have been something like
  *value = (!!(isr0 & PCIE_MSG_PM_PME_MASK)) << 16,
but we are better of using an if() and using the proper macro for this
bit.

Link: https://lore.kernel.org/r/20220110015018.26359-15-kabel@kernel.org
Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit ed750e22e44366e264bcdf7b1cf0713f08f7980a)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>