ARMV7: Vexpress: fix build errors

This patch fixes build errors in the vexpress system:
  - Removed sys_proto.h requirement from syslib.c.
  - Switched vexpress to the default armv7 linker script.
  - Renamed TEXT_BASE to CONFIG_SYS_TEXT_BASE.

Signed-off-by: Matt Waddel <matt.waddel@linaro.org>
diff --git a/board/armltd/vexpress/config.mk b/board/armltd/vexpress/config.mk
index 2d797d7..36395f2 100644
--- a/board/armltd/vexpress/config.mk
+++ b/board/armltd/vexpress/config.mk
@@ -19,5 +19,4 @@
 #
 # Linux-Kernel is expected to be at 0x60008000
 #
-TEXT_BASE = 0x60800000
-LDSCRIPT := $(SRCTREE)/board/armltd/vexpress/u-boot.lds
+CONFIG_SYS_TEXT_BASE = 0x60800000