target/arm: Handle AArch64 in TYPE_ARM_CPU gdb_arch_name

target/arm: Handle AArch64 in TYPE_ARM_CPU gdb_arch_name

Instead of having the TYPE_AARCH64_CPU subclass set
CPUClass::gdb_arch_name to a different function, make the
TYPE_ARM_CPU implementation of the method handle AArch64.

For the moment we make the "is this AArch64?" function test "is the
CPU of TYPE_AARCH64_CPU?", so that this produces no behavioural
change.  When we've moved all the gdbstub related methods across to
the base class, we will be able to change this to be "does the CPU
have the ARM_FEATURE_AARCH64 feature?".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250317142819.900029-4-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>