armv7m_nvic.h: Move from include/hw/arm to include/hw/intc

armv7m_nvic.h: Move from include/hw/arm to include/hw/intc

The armv7m_nvic.h header file was accidentally placed in
include/hw/arm; move it to include/hw/intc to match where
its corresponding .c file lives.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1501692241-23310-15-git-send-email-peter.maydell@linaro.org