ar71xx/mikrotik: enable small sector erase in the m25p80 driver

The serial flash devices used on the ROuterBOARDs are
supporting 4KiB erase blocks. Enable the small sector
erase option in the m25p80 driver to avoid superfluous
erase/write of adjacent blocks.

Signed-off-by: Gabor Juhos <[email protected]>

SVN-Revision: 39696

target/linux/ar71xx/mikrotik/config-default

@@ -86,6 +86,7 @@ CONFIG_ATH79_ROUTERBOOT=y
 CONFIG_CMDLINE="rootfstype=yaffs noinitrd"
 # CONFIG_JFFS2_FS is not set
 CONFIG_LEDS_RB750=y
+CONFIG_M25PXX_PREFER_SMALL_SECTOR_ERASE=y
 CONFIG_MDIO_BITBANG=y
 CONFIG_MDIO_GPIO=y
 # CONFIG_MTD_CFI is not set