uaccess: provide a generic TASK_SIZE_MAX definition

Define TASK_SIZE_MAX as TASK_SIZE if not otherwise defined.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

include/linux/uaccess.h

@@ -31,6 +31,10 @@ typedef struct {
 	/* empty dummy */
 } mm_segment_t;
 
+#ifndef TASK_SIZE_MAX
+#define TASK_SIZE_MAX			TASK_SIZE
+#endif
+
 #define uaccess_kernel()		(false)
 #define user_addr_max()			(TASK_SIZE_MAX)