i8259_internal.h: rename TYPE_I8259_COMMON to i8259-common

This is to emphasise that child types of PIC_COMMON are all instances of an
an 8259 PIC.

Signed-off-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-ID: <20261019120517.1448687-3-mark.caveayland@nutanix.com>
1 file changed