x86/uaccess: Remove unused __addr_ok() macro

This was caught while staring at the whole {set,get}_fs() machinery.

It's last user, the 32-bit version of strnlen_user() went away with

  5723aa993d ("x86: use the new generic strnlen_user() function")

so drop it.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: the arch/x86 maintainers <x86@kernel.org>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Link: https://lkml.kernel.org/r/20190225191109.7671-1-bp@alien8.de

arch/x86/include/asm/uaccess.h

@@ -35,10 +35,7 @@ static inline void set_fs(mm_segment_t fs)
 }
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
-
 #define user_addr_max() (current->thread.addr_limit.seg)
-#define __addr_ok(addr) 	\
-	((unsigned long __force)(addr) < user_addr_max())
 
 /*
  * Test whether a block of memory is a valid user space address.