Add support for transferring the POR_EL0 register between the Linux
kernel and GDB during remote debugging.

This patch implements the necessary `fill` and `store` operations using
the `NT_ARM_POE` regset, allowing GDB to read and write the POR_EL0
register when debugging a remote target that supports FEAT_S1POE.

Approved-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
---
 gdbserver/linux-aarch64-low.cc | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)