hw/core/cpu: Return static value with gdb_arch_name()

hw/core/cpu: Return static value with gdb_arch_name()

All implementations of gdb_arch_name() returns dynamic duplicates of
static strings. It's also unlikely that there will be an implementation
of gdb_arch_name() that returns a truly dynamic value due to the nature
of the function returning a well-known identifiers. Qualify the value
gdb_arch_name() with const and make all of its implementations return
static strings.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230912224107.29669-8-akihiko.odaki@daynix.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20231009164104.369749-15-alex.bennee@linaro.org>