staging: most: video: fix registration of an empty comp core_component

Currently we have structrues comp (which is empty) and comp_info being
used to register and deregister the component.  This mismatch in naming
occurred from a previous commit that renamed aim_info to comp. Fix this
to use consistent component naming in line with most/net, most/sound etc.

This fixes the message two issues, one with a null empty name when
loading the module:

[ 1485.269515] most_core: registered new core component (null)

and an Oops when removing the module:

[ 1485.277971] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 1485.278648] PGD 0 P4D 0
[ 1485.279253] Oops: 0002 [#2] SMP PTI
[ 1485.279847] CPU: 1 PID: 32629 Comm: modprobe Tainted: P      D WC OE     4.18.0-8-generic #9
[ 1485.280442] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
[ 1485.281040] RIP: 0010:most_deregister_component+0x3c/0x70 [most_core]
.. etc

Fixes: 1b10a031 ("staging: most: video: remove aim designators")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>