Makefile: move fs/fat/ entry to drivers/Makefile

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/Makefile b/Makefile
index c04917f..b8713a4 100644
--- a/Makefile
+++ b/Makefile
@@ -243,8 +243,7 @@
 LIBS-$(CONFIG_IXP4XX_NPE) += drivers/net/npe/
 LIBS-$(CONFIG_OF_EMBED) += dts/
 LIBS-y += arch/$(ARCH)/lib/
-LIBS-y += fs/ \
-	fs/fat/
+LIBS-y += fs/
 LIBS-y += net/
 LIBS-y += disk/
 LIBS-y += drivers/