cache_helpers.s:fix mixed tabs and spaces

Change-Id: I8b7c7888d09200410e1a1c11a070c94dd8013ea7
Signed-off-by: Joel Hutton <Joel.Hutton@Arm.com>

lib/aarch32/cache_helpers.S

@@ -90,7 +90,7 @@ endfunc inv_dcache_range
 	.endm
 
 func do_dcsw_op
-	push	{r4-r12,lr}
+	push	{r4-r12, lr}
 	adr	r11, dcsw_loop_table	// compute cache op based on the operation type
 	add	r6, r11, r0, lsl #3	// cache op is 2x32-bit instructions
 loop1:
@@ -133,7 +133,7 @@ level_done:
 	stcopr	r6, CSSELR		//select cache level 0 in csselr
 	dsb	sy
 	isb
-	pop	{r4-r12,pc}
+	pop	{r4-r12, pc}
 
 dcsw_loop_table:
 	stcopr	r0, DCISW