sparc64: fix pci_iounmap() when CONFIG_PCI is not set

stable inclusion
from stable-5.10.72
commit b114f2d18e0f97e2776ccfd877f88b3f30ba54a9
bugzilla: 182982 https://gitee.com/openeuler/kernel/issues/I4I3L1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b114f2d18e0f97e2776ccfd877f88b3f30ba54a9

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

[ Upstream commit d8b1e10a ]

Guenter reported [1] that the pci_iounmap() changes remain problematic,
with sparc64 allnoconfig and tinyconfig still not building due to the
header file changes and confusion with the arch-specific pci_iounmap()
implementation.

I'm pretty convinced that sparc should just use GENERIC_IOMAP instead of
doing its own thing, since it turns out that the sparc64 version of
pci_iounmap() is somewhat buggy (see [2]).  But in the meantime, this
just fixes the build by avoiding the trivial re-definition of the empty
case.

Link: https://lore.kernel.org/lkml/20210920134424.GA346531@roeck-us.net/ [1]
Link: https://lore.kernel.org/lkml/CAHk-=wgheheFx9myQyy5osh79BAazvmvYURAtub2gQtMvLrhqQ@mail.gmail.com/ [2]
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/sparc/lib/iomap.c

@@ -19,8 +19,10 @@ void ioport_unmap(void __iomem *addr)
 EXPORT_SYMBOL(ioport_map);
 EXPORT_SYMBOL(ioport_unmap);
 
+#ifdef CONFIG_PCI
 void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
 {
 	/* nothing to do */
 }
 EXPORT_SYMBOL(pci_iounmap);
+#endif