powerpc/pci: Fix PHB numbering when using opal-phbid

stable inclusion
from stable-v5.10.137
commit cadeb5186e253ba9e44284423621090f1e2420e6
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cadeb5186e253ba9e44284423621090f1e2420e6



--------------------------------

[ Upstream commit f4b39e88 ]

The recent change to the PHB numbering logic has a logic error in the
handling of "ibm,opal-phbid".

When an "ibm,opal-phbid" property is present, &prop is written to and
ret is set to zero.

The following call to of_alias_get_id() is skipped because ret == 0.

But then the if (ret >= 0) is true, and the body of that if statement
sets prop = ret which throws away the value that was just read from
"ibm,opal-phbid".

Fix the logic by only doing the ret >= 0 check in the of_alias_get_id()
case.

Fixes: 0fe1e96f ("powerpc/pci: Prefer PCI domain assignment via DT 'linux,pci-domain' and alias")
Reviewed-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220802105723.1055178-1-mpe@ellerman.id.au


Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>