regulator: tps6594-regulator: Remove a useless static qualifier

There is no point in having 'npname' a static variable. So remove the
static qualifier. This is cleaner and saves a few bytes.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  27949	  12176	     64	  40189	   9cfd	drivers/regulator/tps6594-regulator.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  27947	  12112	      0	  40059	   9c7b	drivers/regulator/tps6594-regulator.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/ebc53d4049ec19796ef07e1bb734de19a2814727.1748103005.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: tititiou36

drivers/regulator/tps6594-regulator.c

@@ -563,7 +563,7 @@ static int tps6594_regulator_probe(struct platform_device *pdev)
 	bool buck_configured[BUCK_NB] = { false };
 	bool buck_multi[MULTI_PHASE_NB] = { false };
 
-	static const char *npname;
+	const char *npname;
 	int error, i, irq, multi;
 	int irq_idx = 0;
 	int buck_idx = 0;