When a SIGSEGV is caused by a Permission Overlay violation, include
additional information in GDB's error message to help identify the
failing address along with the responsible protection key causing
this fault.

Example:
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault
Protection Key Violation while accessing address 0x0000fffff7ff3000 with Protection Key = 1.
0x0000aaaaaaaa0a3c in main () at poe_sigsegv.c:26

Approved-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
---
 gdb/aarch64-linux-tdep.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)