media: platform: renesas-ceu: Fix CSTRST_CPON mask

The CSTRST_CPON mask was wrongly assigned to BIT(1) instead of BIT(0).
Fix that by changing the mask opportunely.

Reported-by: Dylan Laduranty <dylan.laduranty@mesotic.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>