arm64: dts: qcom: sdm845: kill IPA modem-remoteproc property

The "modem-remoteproc" property is no longer required for the IPA
driver, so get rid of it.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit 5da1fca9)