Convert CONFIG_EFLASH_PROTSECTORS to Kconfig

This converts the following to Kconfig:
   CONFIG_EFLASH_PROTSECTORS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/ethernut5_defconfig b/configs/ethernut5_defconfig
index da8c0bd..256f652 100644
--- a/configs/ethernut5_defconfig
+++ b/configs/ethernut5_defconfig
@@ -6,6 +6,7 @@
 CONFIG_SYS_MALLOC_LEN=0x121000
 CONFIG_TARGET_ETHERNUT5=y
 CONFIG_AT91_EFLASH=y
+CONFIG_EFLASH_PROTSECTORS=1
 CONFIG_NR_DRAM_BANKS=1
 CONFIG_ENV_SIZE=0x21000
 CONFIG_ENV_OFFSET=0x3DE000