powerpc/pseries/htmdump: Add memory configuration dump support to htmdump module

powerpc/pseries/htmdump: Add memory configuration dump support to htmdump module

H_HTM (Hardware Trace Macro) hypervisor call has capability
to capture SystemMemory Configuration. This information
helps to understand the address mapping for the partitions
in the system.

Support dumping system memory configuration from Hardware
Trace Macro (HTM) function via debugfs interface. Under
debugfs folder "/sys/kernel/debug/powerpc/htmdump", add
file "htmsystem_mem".

The interface allows only read of this file which will present the
content of HTM buffer from the hcall. The 16th offset of HTM
buffer has value for the number of entries for array of processors.
Use this information to copy data to the debugfs file

Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260314132953.27269-1-atrajeev@linux.ibm.com