mtd: rawnand: denali: remove hard-coded DENALI_DEFAULT_OOB_SKIP_BYTES

As commit 0d55c66 (mtd: rawnand: denali: set SPARE_AREA_SKIP_BYTES
register to 8 if unset") says, there were three solutions discussed:

  [1] Add a DT property to specify the skipped bytes in OOB
  [2] Associate the preferred value with compatible
  [3] Hard-code the default value in the driver

At that time, [3] was chosen because I did not have enough information
about the other platforms than UniPhier.

That commit also says "The preferred value may vary by platform. If so,
please trade up to a different solution." My intention was to replace
[3] with [2], not keep both [2] and [3].

Now that we have switched to [2] for SOCFPGA's SPARE_AREA_SKIP_BYTES=2,
[3] should be removed. This should be OK because denali_pci.c just
gets back to the original behavior.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

drivers/mtd/nand/raw/denali.c

@@ -21,7 +21,6 @@
 #include "denali.h"
 
 #define DENALI_NAND_NAME    "denali-nand"
-#define DENALI_DEFAULT_OOB_SKIP_BYTES	8
 
 /* for Indexed Addressing */
 #define DENALI_INDEXED_CTRL	0x00
@@ -1302,22 +1301,16 @@ int denali_init(struct denali_controller *denali)
 
 	/*
 	 * Set how many bytes should be skipped before writing data in OOB.
-	 * If a non-zero value has already been configured, update it in HW.
-	 * If a non-zero value has already been set (by firmware or something),
-	 * just use it. Otherwise, set the driver's default.
+	 * If a platform requests a non-zero value, set it to the register.
+	 * Otherwise, read the value out, expecting it has already been set up
+	 * by firmware.
 	 */
-	if (denali->oob_skip_bytes) {
+	if (denali->oob_skip_bytes)
 		iowrite32(denali->oob_skip_bytes,
 			  denali->reg + SPARE_AREA_SKIP_BYTES);
-	} else {
-		denali->oob_skip_bytes =
-			ioread32(denali->reg + SPARE_AREA_SKIP_BYTES);
-		if (!denali->oob_skip_bytes) {
-			denali->oob_skip_bytes = DENALI_DEFAULT_OOB_SKIP_BYTES;
-			iowrite32(denali->oob_skip_bytes,
-				  denali->reg + SPARE_AREA_SKIP_BYTES);
-		}
-	}
+	else
+		denali->oob_skip_bytes = ioread32(denali->reg +
+						  SPARE_AREA_SKIP_BYTES);
 
 	iowrite32(0, denali->reg + TRANSFER_SPARE_REG);
 	iowrite32(GENMASK(denali->nbanks - 1, 0), denali->reg + RB_PIN_ENABLED);