This new driver version uses the DMA mapping interface

introduced in FreeBSD-4.0. The driver is now full up-to-date
with regards to the current kernel interfaces.

Another significant change in this driver version applies
to the checking of the data direction. The driver is now
able to check against the expected data direction in any
circumstance and will not hang either if direction is wrong
at the start of the IO, or if for some weird reason,
the device changes to the wrong direction during the IO.

This driver version is still usable under FreeBSD 3.2/3.3,
since it only requires CAM, other kernel interface dependencies
being #if'ed in the sources according to kernel version.
But, in order to use the driver under those early kernel
versions, user has to move the driver sources by hand and make
appropriate tiny changes to let the kernel know about the driver.

Other changes:
- Remove the debugging stuff for WSR bit.
- Get rid of some warnings about volatile being discarded.

sys/dev/sym/sym_conf.h

@@ -123,12 +123,6 @@
  */
 /* #define SYM_CONF_IARB_SUPPORT */
 
-/*
- *  Not needed on FreeBSD, since the system allocator 
- *  does provide naturally aligned addresses.
- */
-#define	SYM_CONF_USE_INTERNAL_ALLOCATOR
-
 /*-------------------------------------------------------------------
  *  Configuration that could be dynamic if it was possible 
  *  to pass arguments to the driver.