include/types.h: Provide BIT() macro

This macro is controversial for arches where the bits are numbered
MSb first, though we don't support such an arch. We've seen this macro
creep into our tree in different places, so provide it in one place.

Change-Id: I86cd8a16420f34ef31b615aec4e0f7bd3191ca35
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/8280
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@gmail.com>
Reviewed-by: David Hendricks <dhendrix@chromium.org>

src/include/types.h

@@ -22,6 +22,13 @@
 #include <stdint.h>
 #include <stddef.h>
 
+/*
+ * This may mean something else on architectures where the bits are numbered
+ * from the MSB (e.g. PowerPC), but until we cross that bridge, this macro is
+ * perfectly fine.
+ */
+#define BIT(x)				(1ul << (x))
+
 /**
  * Coreboot error codes
  *