bcm53xx: backport forgotten spi-nor change

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

SVN-Revision: 43031

target/linux/bcm53xx/patches-3.14/002-mtd-spi-nor-from-3.18.patch

@@ -104,3 +104,26 @@
  		nor->erase_opcode = SPINOR_OP_SE;
  		mtd->erasesize = info->sector_size;
  	}
+--- a/drivers/mtd/spi-nor/Kconfig
++++ b/drivers/mtd/spi-nor/Kconfig
+@@ -7,6 +7,20 @@ menuconfig MTD_SPI_NOR
+ 
+ if MTD_SPI_NOR
+ 
++config MTD_SPI_NOR_USE_4K_SECTORS
++	bool "Use small 4096 B erase sectors"
++	default y
++	help
++	  Many flash memories support erasing small (4096 B) sectors. Depending
++	  on the usage this feature may provide performance gain in comparison
++	  to erasing whole blocks (32/64 KiB).
++	  Changing a small part of the flash's contents is usually faster with
++	  small sectors. On the other hand erasing should be faster when using
++	  64 KiB block instead of 16 × 4 KiB sectors.
++
++	  Please note that some tools/drivers/filesystems may not work with
++	  4096 B erase size (e.g. UBIFS requires 15 KiB as a minimum).
++
+ config SPI_FSL_QUADSPI
+ 	tristate "Freescale Quad SPI controller"
+ 	depends on ARCH_MXC