xtensa: update XDM register map for TRAX support

- Include additional debug module registers
- Add translation function for DM reg addr -> ID
- Add DM read/write commands

Signed-off-by: ianst <ianst@cadence.com>
Change-Id: If95419d24a9f27a40fa695c8c15326cdfd127ef1
Reviewed-on: https://review.openocd.org/c/openocd/+/7973
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins

doc/openocd.texi

@@ -11487,6 +11487,12 @@ Execute arbitrary instruction(s) provided as an ascii string.  The string repres
 number of instruction bytes, thus its length must be even.
 @end deffn
 
+@deffn {Command} {xtensa dm} (address) [value]
+Read or write Xtensa Debug Module (DM) registers.  @var{address} is required for both reads
+and writes and is a 4-byte-aligned value typically between 0 and 0x3ffc.  @var{value} is specified
+only for write accesses.
+@end deffn
+
 @subsection Xtensa Performance Monitor Configuration
 
 @deffn {Command} {xtensa perfmon_enable} <counter_id> <select> [mask] [kernelcnt] [tracelevel]