percpu: replace __ASSEMBLY__ with __ASSEMBLER__ in percpu-defs.h header file

While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembly code, __ASSEMBLY__ is a macro that
only gets defined by the Makefiles in the kernel.  This can be very
confusing when switching between userspace and kernelspace coding, or when
dealing with uapi headers that rather should use __ASSEMBLER__ instead. 
So let's standardize now on the __ASSEMBLER__ macro that is provided by
the compilers.

This is a completely mechanical patch (done with a simple "sed -i"
statement.

Link: https://lore.kernel.org/20260619154704.41293-1-thuth@redhat.com
Signed-off-by: Thomas Huth <thuth@redhat.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/percpu-defs.h

@@ -203,7 +203,7 @@
 /*
  * Accessors and operations.
  */
-#ifndef __ASSEMBLY__
+#ifndef __ASSEMBLER__
 
 /*
  * __verify_pcpu_ptr() verifies @ptr is a percpu pointer without evaluating
@@ -514,5 +514,5 @@ do {									\
 #define this_cpu_inc_return(pcp)	this_cpu_add_return(pcp, 1)
 #define this_cpu_dec_return(pcp)	this_cpu_add_return(pcp, -1)
 
-#endif /* __ASSEMBLY__ */
+#endif /* __ASSEMBLER__ */
 #endif /* _LINUX_PERCPU_DEFS_H */