media: i2c: Use div64_ul() for u64-by-unsigned-long divide

div_u64() does a 64-by-32 division, while the divisor max2175.xtal_freq
is unsigned long, thus 64-bit on 64-bit platforms.  Hence the proper
function to call is div64_ul().

Note that this change does not have any functional impact, as the
crystal frequency must be much lower than the 32-bit limit anyway.
On 32-bit platforms, the generated code is the same.  But at least on
arm64, this saves an AND-instruction to truncate xtal_freq to 32-bit.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>