media: atomisp: fix mask and shift operation on ISPSSPM0

Currently the check on bits 25:24 on ISPSSPM0 is always 0 because
the mask and shift operations are incorrect. Fix this by shifting
by MRFLD_ISPSSPM0_ISPSSS_OFFSET (24 bits right) and then masking
with RFLD_ISPSSPM0_ISPSSC_MASK (0x03) to get the appropriate 2 bits
to check.

Addresses-Coverity: ("Operands don't affect result")
Fixes: 0f441fd7

 ("media: atomisp: simplify the power down/up code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>