treewide: remove current_text_addr

Prefer _THIS_IP_ defined in linux/kernel.h.

Most definitions of current_text_addr were the same as _THIS_IP_, but
a few archs had inline assembly instead.

This patch removes the final call site of current_text_addr, making all
of the definitions dead code.

[akpm@linux-foundation.org: fix arch/csky/include/asm/processor.h]
Link: http://lkml.kernel.org/r/20180911182413.180715-1-ndesaulniers@google.com
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/ia64/include/asm/processor.h

@@ -602,12 +602,6 @@ ia64_set_unat (__u64 *unat, void *spill_addr, unsigned long nat)
 	*unat = (*unat & ~mask) | (nat << bit);
 }
 
-/*
- * Get the current instruction/program counter value.
- */
-#define current_text_addr() \
-	({ void *_pc; _pc = (void *)ia64_getreg(_IA64_REG_IP); _pc; })
-
 static inline __u64
 ia64_get_ivr (void)
 {