From: Stanislav Kinsburskii <stanislav.kinsburskii@gmail.com>

These helper function - virt_to_phys - doesn't need the address pointer to
be mutable.

In the same time expecting it to be mutable leads to the following build
warning for constant pointers:

  warning: passing argument 1 of ‘virt_to_phys’ discards ‘const’ qualifier from pointer target type

Signed-off-by: Stanislav Kinsburskii <stanislav.kinsburskii@gmail.com>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Nicholas Piggin <npiggin@gmail.com>
CC: Christophe Leroy <christophe.leroy@csgroup.eu>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
CC: Bjorn Helgaas <bhelgaas@google.com>
CC: Stanislav Kinsburskii <stanislav.kinsburskii@gmail.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-kernel@vger.kernel.org
---
 arch/powerpc/include/asm/io.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index f1e657c9bbe8..c287eeb9536f 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -959,7 +959,7 @@ extern void __iomem *__ioremap_caller(phys_addr_t, unsigned long size,
  *	almost all conceivable cases a device driver should not be using
  *	this function
  */
-static inline unsigned long virt_to_phys(volatile void * address)
+static inline unsigned long virt_to_phys(const volatile void * address)
 {
 	WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && !virt_addr_valid(address));