boot/arm-trusted-firmware: fix coding-style

Fix coding style issue introduced in cf176128ec4a (boot/arm-trusted-firmware:
add SSP option)

Fixes: cf176128ec4ad60c29c8828cab1887f69edb9473

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

boot/arm-trusted-firmware/Config.in

@@ -190,9 +190,9 @@ config BR2_TARGET_ARM_TRUSTED_FIRMWARE_NEEDS_ARM32_TOOLCHAIN
 
 config BR2_TARGET_ARM_TRUSTED_FIRMWARE_SSP
 	bool "Build with SSP"
+	default y
 	depends on BR2_TOOLCHAIN_HAS_SSP
 	depends on !BR2_SSP_NONE
-	default y
 	help
 	  Say 'y' here if you want to build ATF with SSP.