hw/arm/nrf51: Rename ARMv7MState 'cpu' -> 'armv7m'

The ARMv7MState object is not simply a CPU, it also
contains the NVIC, SysTick timer, and various MemoryRegions.

Rename the field as 'armv7m', like other Cortex-M boards.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20250112225614.33723-2-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2 files changed