We don't use this carveout on trogdor boards, and having it defined in
the sc7180 SoC file causes an overlap message to be printed at boot.

 OF: reserved mem: OVERLAP DETECTED!
 memory@86000000 (0x0000000086000000--0x000000008ec00000) overlaps with memory@8b700000 (0x000000008b700000--0x000000008b710000)

Delete the node in the trogdor dtsi file to fix the overlap problem and
remove the error message.

Cc: Alex Elder <elder@linaro.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Fixes: 310b2666 ("arm64: dts: qcom: sc7180: define ipa_fw_mem node")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220517193307.3034602-1-swboyd@chromium.org