net: ipa: Fix programming of QTIME_TIMESTAMP_CFG

net: ipa: Fix programming of QTIME_TIMESTAMP_CFG

The 'val' variable gets overwritten multiple times, discarding previous
values. Looking at the git log shows these should be combined with |=
instead.

Fixes: 9265a4f0f0b4 ("net: ipa: define even more IPA register fields")
Link: https://sashiko.dev/#/patchset/20260403-milos-ipa-v1-0-01e9e4e03d3e%40fairphone.com?part=4
Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://patch.msgid.link/20260409-ipa-fixes-v1-1-a817c30678ac@fairphone.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>