arm64: memory: Make virt_to_pfn() a static inline

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Since arm64 is using <asm-generic/memory_model.h> to provide
__phys_to_pfn() we need to move the inclusion of that header
up, so we can resolve the static inline at compile time.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm64/include/asm/memory.h

@@ -331,6 +331,14 @@ static inline void *phys_to_virt(phys_addr_t x)
 	return (void *)(__phys_to_virt(x));
 }
 
+/* Needed already here for resolving __phys_to_pfn() in virt_to_pfn() */
+#include <asm-generic/memory_model.h>
+
+static inline unsigned long virt_to_pfn(const void *kaddr)
+{
+	return __phys_to_pfn(virt_to_phys(kaddr));
+}
+
 /*
  * Drivers should NOT use these either.
  */
@@ -339,7 +347,6 @@ static inline void *phys_to_virt(phys_addr_t x)
 #define __pa_nodebug(x)		__virt_to_phys_nodebug((unsigned long)(x))
 #define __va(x)			((void *)__phys_to_virt((phys_addr_t)(x)))
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
-#define virt_to_pfn(x)		__phys_to_pfn(__virt_to_phys((unsigned long)(x)))
 #define sym_to_pfn(x)		__phys_to_pfn(__pa_symbol(x))
 
 /*