ramips: enable 4K sector support in kernel config

This is a follow up to 28110727f1
"ramips: set blocksize for 4MB devices". I've missed to include the
required changes of the kernel configs to enable 4K sector size
support.

The option is only enabled for targets having boards with 4k sector
size flash chips.

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/mt7620/config-4.4

@@ -137,6 +137,7 @@ CONFIG_MTD_M25P80=y
 CONFIG_MTD_NAND_MT7620=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_MTD_SPI_NOR=y
+CONFIG_MTD_SPI_NOR_USE_4K_SECTORS=y
 CONFIG_MTD_SPLIT_FIRMWARE=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_SPLIT_TPLINK_FW=y

target/linux/ramips/mt7621/config-4.4

@@ -159,6 +159,7 @@ CONFIG_MTD_NAND=y
 CONFIG_MTD_NAND_ECC=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_MTD_SPI_NOR=y
+CONFIG_MTD_SPI_NOR_USE_4K_SECTORS=y
 CONFIG_MTD_SPLIT_FIRMWARE=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_SPLIT_TRX_FW=y

target/linux/ramips/rt305x/config-4.4

@@ -131,6 +131,7 @@ CONFIG_MTD_CMDLINE_PARTS=y
 CONFIG_MTD_M25P80=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_MTD_SPI_NOR=y
+CONFIG_MTD_SPI_NOR_USE_4K_SECTORS=y
 CONFIG_MTD_SPLIT_FIRMWARE=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_SPLIT_UIMAGE_FW=y

target/linux/ramips/rt3883/config-4.4

@@ -130,6 +130,7 @@ CONFIG_MTD_CMDLINE_PARTS=y
 CONFIG_MTD_M25P80=y
 CONFIG_MTD_PHYSMAP=y
 CONFIG_MTD_SPI_NOR=y
+CONFIG_MTD_SPI_NOR_USE_4K_SECTORS=y
 CONFIG_MTD_SPLIT_FIRMWARE=y
 CONFIG_MTD_SPLIT_SEAMA_FW=y
 CONFIG_MTD_SPLIT_UIMAGE_FW=y