tegra: usb: move implementation into right directory

This moves the Tegra USB implementation into the drivers/usb/host
directory. Note that this merges the old
/arch/arm/cpu/armv7/tegra20/usb.c file into ehci-tegra.c. No code
changes, just moving stuff around.

v2: While at it also move some defines and the usb.h header file to make
usb driver usable for Tegra30.
NOTE: A lot more work is required to properly init the PHYs and PLL_U on
Tegra30, this is just to make porting easier and it does no harm here.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/include/asm/arch-tegra30/tegra.h b/arch/arm/include/asm/arch-tegra30/tegra.h
index decf564..c02c5d8 100644
--- a/arch/arm/include/asm/arch-tegra30/tegra.h
+++ b/arch/arm/include/asm/arch-tegra30/tegra.h
@@ -21,6 +21,8 @@
 
 #include <asm/arch-tegra/tegra.h>
 
+#define TEGRA_USB1_BASE		0x7D000000
+
 #define BCT_ODMDATA_OFFSET	6116	/* 12 bytes from end of BCT */
 
 #define MAX_NUM_CPU		4