core/show-info: 'name' only applies to packages

Commit 0cfa1659 (package/pkg-utils.mk: introduce "name" field in
show-info output) did what it said, but did so in the generic show-info
part, thus it was also added to filesystems (rootfs), the other kind of
entity that show-info reports on.

Only packages have a "name"; filesystems do not. Instead, they already
have an 'image_name'.

Move the 'name' field to the package-related part of show-info.

Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>