uaccess: Add a prototype of non-static __probe_user_read()

Declare a prototype of non-static __probe_user_read() as
same as __probe_kernel_read() at uaccess.h.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

include/linux/uaccess.h

@@ -252,6 +252,7 @@ extern long __probe_kernel_read(void *dst, const void *src, size_t size);
  * happens, handle that and return -EFAULT.
  */
 extern long probe_user_read(void *dst, const void __user *src, size_t size);
+extern long __probe_user_read(void *dst, const void __user *src, size_t size);
 
 /*
  * probe_kernel_write(): safely attempt to write to a location