cmd: pcmcia: Build only if CONFIG_CMD_PCMCIA=y

Signed-off-by: Ismael Luceno <ismael.luceno@silicon-gears.com>
diff --git a/cmd/Makefile b/cmd/Makefile
index 15ae4d2..a127a99 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -104,7 +104,7 @@
 ifdef CONFIG_PCI
 obj-$(CONFIG_CMD_PCI) += pci.o
 endif
-obj-y += pcmcia.o
+obj-$(CONFIG_CMD_PCMCIA) += pcmcia.o
 obj-$(CONFIG_CMD_PINMUX) += pinmux.o
 obj-$(CONFIG_CMD_PXE) += pxe.o
 obj-$(CONFIG_CMD_WOL) += wol.o