dm: Add Hardware Spinlock class

This is uclass for Hardware Spinlocks.
It implements two mandatory operations: lock and unlock
and one optional relax operation.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 4ac823d..e9fbadd 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -40,6 +40,8 @@
 
 source "drivers/gpio/Kconfig"
 
+source "drivers/hwspinlock/Kconfig"
+
 source "drivers/i2c/Kconfig"
 
 source "drivers/input/Kconfig"