Convert CONFIG_NET_RETRY_COUNT to Kconfig

This converts the following to Kconfig:
   CONFIG_NET_RETRY_COUNT

Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/da850evm_direct_nor_defconfig b/configs/da850evm_direct_nor_defconfig
index d40f875..7e06782 100644
--- a/configs/da850evm_direct_nor_defconfig
+++ b/configs/da850evm_direct_nor_defconfig
@@ -50,6 +50,7 @@
 CONFIG_USE_BOOTFILE=y
 CONFIG_BOOTFILE="uImage"
 CONFIG_VERSION_VARIABLE=y
+CONFIG_NET_RETRY_COUNT=10
 CONFIG_BOOTP_SEND_HOSTNAME=y
 CONFIG_DM=y
 CONFIG_DA8XX_GPIO=y