selftests: kvm: s390: Add debug print functions

selftests: kvm: s390: Add debug print functions

Add functions to simply print some basic state information in selftests.

The output can be enabled by setting:

    #define TH_LOG_ENABLED 1
    #define DEBUG 1

* print_psw: current SIE state description and VM run state
* print_hex_bytes: print memory with some counting markers
* print_hex: PRINT_HEX with 512 bytes
* print_run: use print_psw and print_hex to print contents of VM run
  state and SIE state description
* print_regs: print content of general and control registers

All prints use pr_debug for the output and can be configured using
DEBUG.

Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20240807154512.316936-6-schlameuss@linux.ibm.com
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20240807154512.316936-6-schlameuss@linux.ibm.com>