nir: make nir_instrs_equal() static

This was previously tied to CSE, since it would only work for
instructions where nir_can_cse() (now instr_can_rewrite()) returned
true. Now that CSE uses the instruction set abstraction which only uses
this internally, we can make it local to nir_instr_set.c.

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Signed-off-by: Connor Abbott <cwabbott0@gmail.com>

src/glsl/nir/nir_instr_set.c

@@ -247,7 +247,7 @@ nir_alu_srcs_equal(const nir_alu_instr *alu1, const nir_alu_instr *alu2,
  * the same hash for (ignoring collisions, of course).
  */
 
-bool
+static bool
 nir_instrs_equal(const nir_instr *instr1, const nir_instr *instr2)
 {
    if (instr1->type != instr2->type)

src/glsl/nir/nir_instr_set.h

@@ -25,8 +25,6 @@
 
 #include "nir.h"
 
-bool nir_instrs_equal(const nir_instr *instr1, const nir_instr *instr2);
-
 /**
  * This file defines functions for creating, destroying, and manipulating an
  * "instruction set," which is an abstraction for finding duplicate