ARM: mm: kill unused runtime hook arch_iounmap()

Since the following commits,

v5.4
  commit 59d3ae9a ("ARM: remove Intel iop33x and iop13xx support")
v5.11
  commit 3e3f354b ("ARM: remove ebsa110 platform")

The runtime hook arch_iounmap() on ARM is useless, kill arch_iounmap()
and __iounmap().

Cc: Russell King <linux@armlinux.org.uk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20220607125027.44946-2-wangkefeng.wang@huawei.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm/include/asm/io.h

@@ -139,11 +139,9 @@ extern void __iomem *__arm_ioremap_caller(phys_addr_t, size_t, unsigned int,
 extern void __iomem *__arm_ioremap_pfn(unsigned long, unsigned long, size_t, unsigned int);
 extern void __iomem *__arm_ioremap_exec(phys_addr_t, size_t, bool cached);
 void __arm_iomem_set_ro(void __iomem *ptr, size_t size);
-extern void __iounmap(volatile void __iomem *addr);
 
 extern void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t,
 	unsigned int, void *);
-extern void (*arch_iounmap)(volatile void __iomem *);
 
 /*
  * Bad read/write accesses...
@@ -380,7 +378,7 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size);
 #define ioremap_wc ioremap_wc
 #define ioremap_wt ioremap_wc
 
-void iounmap(volatile void __iomem *iomem_cookie);
+void iounmap(volatile void __iomem *io_addr);
 #define iounmap iounmap
 
 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size);

arch/arm/mm/ioremap.c

@@ -418,7 +418,7 @@ void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 						   __builtin_return_address(0));
 }
 
-void __iounmap(volatile void __iomem *io_addr)
+void iounmap(volatile void __iomem *io_addr)
 {
 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 	struct static_vm *svm;
@@ -446,13 +446,6 @@ void __iounmap(volatile void __iomem *io_addr)
 
 	vunmap(addr);
 }
-
-void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
-
-void iounmap(volatile void __iomem *cookie)
-{
-	arch_iounmap(cookie);
-}
 EXPORT_SYMBOL(iounmap);
 
 #if defined(CONFIG_PCI) || IS_ENABLED(CONFIG_PCMCIA)

arch/arm/mm/nommu.c

@@ -230,14 +230,7 @@ void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 	return (void *)phys_addr;
 }
 
-void __iounmap(volatile void __iomem *addr)
-{
-}
-EXPORT_SYMBOL(__iounmap);
-
-void (*arch_iounmap)(volatile void __iomem *);
-
-void iounmap(volatile void __iomem *addr)
+void iounmap(volatile void __iomem *io_addr)
 {
 }
 EXPORT_SYMBOL(iounmap);