mtd: spi-nor: Fix the disabling of write protection at init

spi_nor_spansion_clear_sr_bp() depends on spansion_quad_enable().
While spansion_quad_enable() is selected as default when
initializing the flash parameters, the nor->quad_enable() method
can be overwritten later on when parsing BFPT.

Select the write protection disable mechanism at spi_nor_init() time,
when the nor->quad_enable() method is already known.

Fixes: 191f5c2ed4b6faba ("mtd: spi-nor: use 16-bit WRR command when QE is set on spansion flashes")
Signed-off-by: Tudor Ambarus <[e-mail]>
Reviewed-by: Vignesh Raghavendra <[e-mail]>
Signed-off-by: Richard Weinberger <[e-mail]>

drivers/mtd/spi-nor/spi-nor.c

···
 		default:
 			/* Kept only for backward compatibility purpose. */
 			params->quad_enable = spansion_quad_enable;
-			if (nor->clear_sr_bp)
-				nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
 			break;
 		}
 
···
 	int err;
 
 	if (nor->clear_sr_bp) {
+		if (nor->quad_enable == spansion_quad_enable)
+			nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
+
 		err = nor->clear_sr_bp(nor);
 		if (err) {
 			dev_err(nor->dev,