x86: Move CONFIG_X86_RESET_VECTOR and CONFIG_SYS_X86_START16 to Kconfig

Convert CONFIG_X86_RESET_VECTOR and CONFIG_SYS_X86_START16 to Kconfig
options so that we can remove them from board configuration file.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ffcb4cb..ba0c1aa 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -66,6 +66,15 @@
 config SMM_TSEG_SIZE
 	hex
 
+config X86_RESET_VECTOR
+	bool
+	default n
+
+config SYS_X86_START16
+	hex
+	depends on X86_RESET_VECTOR
+	default 0xfffff800
+
 config BOARD_ROMSIZE_KB_512
 	bool
 config BOARD_ROMSIZE_KB_1024