platform/x86: i2c-multi-instantiate: Rename it for a generic serial driver name

platform/x86: i2c-multi-instantiate: Rename it for a generic serial driver name

BugLink: https://bugs.launchpad.net/bugs/1965496
Rename I2C multi instantiate driver to serial-multi-instantiate for
upcoming addition of SPI support

Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220121172431.6876-6-sbinding@opensource.cirrus.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
(cherry picked from commit 5e63b2ea3dfbab9307e197004a3c5ee4e1442582)
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Paolo Pisati <paolo.pisati@canonical.com>