disas/nanomips: Remove namespace img

disas/nanomips: Remove namespace img

Since there's no namespace feature in C, namespace img has been replaced
with adding the prefix "img" to the namespace members.

Prefix "img" has been added to the function names of functions that used
to be wrapped in namespace img. Those are img::format() functions.
I.e. replaced img::format with the img_format.

Typedef address that used to belong to namespace img now is called
img_address.

Signed-off-by: Milica Lazarevic <milica.lazarevic@syrmia.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220912122635.74032-2-milica.lazarevic@syrmia.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>