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/riscv/include/asm/processor.h

@@ -33,12 +33,6 @@
 struct task_struct;
 struct pt_regs;
 
-/*
- * Default implementation of macro that returns current
- * instruction pointer ("program counter").
- */
-#define current_text_addr()	({ __label__ _l; _l: &&_l; })
-
 /* CPU-specific state of a task */
 struct thread_struct {
 	/* Callee-saved registers */