hw/ide: Rename ide_exec_cmd() -> ide_bus_exec_cmd()

hw/ide: Rename ide_exec_cmd() -> ide_bus_exec_cmd()

ide_exec_cmd() operates on a IDEBus; rename it as
ide_bus_exec_cmd() to emphasize its first argument
is a IDEBus.

Mechanical change using:

  $ sed -i -e 's/ide_exec_cmd/ide_bus_exec_cmd/g' \
        $(git grep -wl ide_exec_cmd)

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230215112712.23110-14-philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>