Refine SPI bitbanging

Change the SPI bitbanging core to fix a subtle bug (which had no
effect so far) and to make integration of the RayeR SPIPGM and Nvidia
MCP6x/MCP7x SPI patches easier. Kill a few global variables and require
explicit initialization of bitbanging delay.

A big to Johannes Sjölund for testing an earlier version of the code as
part of the Nvidia MCP6x/MCP7x SPI bitbanging patch.

Corresponding to flashrom svn r1085.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Michael Karcher <flashrom@mkarcher.dialup.fu-berlin.de>
diff --git a/hwaccess.h b/hwaccess.h
index c38ee6f..a230fa1 100644
--- a/hwaccess.h
+++ b/hwaccess.h
@@ -176,6 +176,10 @@
 #define __DARWIN__
 #endif
 
+/* Clarification about OUTB/OUTW/OUTL argument order:
+ * OUT[BWL](val, port)
+ */
+
 #if defined(__FreeBSD__) || defined(__DragonFly__)
   #include <machine/cpufunc.h>
   #define off64_t off_t