imx31_phycore: Split the eet variant out into a different TARGET

Rename CONFIG_IMX31_PHYCORE_EET to CONFIG_TARGET_IMX31_PHYCORE_EET and
make this a distinct config target.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/imx31_phycore/Kconfig b/board/imx31_phycore/Kconfig
index d3d2025..e897ee1 100644
--- a/board/imx31_phycore/Kconfig
+++ b/board/imx31_phycore/Kconfig
@@ -1,4 +1,4 @@
-if TARGET_IMX31_PHYCORE
+if TARGET_IMX31_PHYCORE || TARGET_IMX31_PHYCORE_EET
 
 config SYS_BOARD
 	default "imx31_phycore"