omapl138_lcdk: Stop using CONFIG_MACH_OMAPL138_LCDK

We have one places that uses this symbol and CONFIG_TARGET_OMAPL138_LCDK
works equally well, switch to that.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/davinci/da8xxevm/Makefile b/board/davinci/da8xxevm/Makefile
index 3fac615..8187c8d 100644
--- a/board/davinci/da8xxevm/Makefile
+++ b/board/davinci/da8xxevm/Makefile
@@ -7,4 +7,4 @@
 
 obj-$(CONFIG_MACH_DAVINCI_DA830_EVM)	+= da830evm.o
 obj-$(CONFIG_MACH_DAVINCI_DA850_EVM)	+= da850evm.o
-obj-$(CONFIG_MACH_OMAPL138_LCDK) += omapl138_lcdk.o
+obj-$(CONFIG_TARGET_OMAPL138_LCDK)	+= omapl138_lcdk.o