cmd: pinmux: Add pinmux command

pinmux command allows to :
 - list all pin-controllers available on platforms
 - select a pin-controller
 - display the muxing of all pins of the current pin-controller
   or all pin-controllers depending of given options

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
cmd: pinmux: Fix pinmux command

if "pinmux status" command is used without having
set dev using "pinmux dev", print pinmux usage
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/Makefile b/cmd/Makefile
index 12a1330..0534ddc 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -103,6 +103,7 @@
 obj-$(CONFIG_CMD_PCI) += pci.o
 endif
 obj-y += pcmcia.o
+obj-$(CONFIG_CMD_PINMUX) += pinmux.o
 obj-$(CONFIG_CMD_PXE) += pxe.o
 obj-$(CONFIG_CMD_WOL) += wol.o
 obj-$(CONFIG_CMD_QFW) += qfw.o