mips: bmips: add missing SFR NeufBox 4 config

Fixes commit a186d26, which missed including SFR NeufBox config from bmips

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
diff --git a/arch/mips/mach-bmips/Kconfig b/arch/mips/mach-bmips/Kconfig
index d168448..4a0c383 100644
--- a/arch/mips/mach-bmips/Kconfig
+++ b/arch/mips/mach-bmips/Kconfig
@@ -63,6 +63,11 @@
 	depends on SOC_BMIPS_BCM6358
 	select BMIPS_SUPPORTS_BOOT_RAM
 
+config BOARD_SFR_NB4_SER
+	bool "SFR NeufBox 4 (Sercomm)"
+	depends on SOC_BMIPS_BCM6358
+	select BMIPS_SUPPORTS_BOOT_RAM
+
 endchoice
 
 choice
@@ -84,5 +89,6 @@
 source "board/comtrend/ar5387un/Kconfig"
 source "board/comtrend/vr3032u/Kconfig"
 source "board/huawei/hg556a/Kconfig"
+source "board/sfr/nb4_ser/Kconfig"
 
 endmenu