[riscv-port-jdk11u:riscv-port] RFR: 8297697: RISC-V: Add support for SATP mode detection

[Gui Cao]

Hi,
Please review this backport to riscv-port-jdk11u.
Backport of [JDK-8297697](https://bugs.openjdk.org/browse/JDK-8297697), and [JDK-8301067](https://bugs.openjdk.org/browse/JDK-8301067). JDK-8301067 only modifies the log description information introduced by JDK-8297697.

After this patch, If it is an unsupported satp.mode , the message will be as follows:

root at qemuriscv64:~/jdk/bin# ./java -version
Error occurred during initialization of VM
Unsupported satp mode: sv57

root at qemuriscv64:~/jdk/bin# cat /proc/cpuinfo
processor       : 0
hart            : 0
isa             : rv64imafdch_zicbom_zicboz_zicntr_zicsr_zifencei_zihintpause_zihpm_zba_zbb_zbs_sstc
mmu             : sv57
mvendorid       : 0x0
marchid         : 0x0
mimpid          : 0x0


Testing:

- [ ] Run tier1 tests on SOPHON SG2042 (release)

-------------

Commit messages:
 - Backport 8297697: RISC-V: Add support for SATP mode detection

Changes: https://git.openjdk.org/riscv-port-jdk11u/pull/19/files
  Webrev: https://webrevs.openjdk.org/?repo=riscv-port-jdk11u&pr=19&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297697
  Stats: 39 lines in 3 files changed: 38 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/riscv-port-jdk11u/pull/19.diff
  Fetch: git fetch https://git.openjdk.org/riscv-port-jdk11u.git pull/19/head:pull/19

PR: https://git.openjdk.org/riscv-port-jdk11u/pull/19