arm64: dts: qcom: sdm845-db845c-navigation-mezzanine: Drop CMA heap

arm64: dts: qcom: sdm845-db845c-navigation-mezzanine: Drop CMA heap

Initially added, the cma heap was supposed to help with libcamera swisp,
however a mistake was made such that the node was never applied as part
of the overlay since the change was added to the overlay root ("/") and
not with a reference to the target dtb root ("&{/}"). Moveover libcamera
doesn't require CMA heap on Qualcomm platforms anymore as it can now use
UDMA buffers instead.

Drop the CMA heap node. This change has no effect on the final dtb.

This reverts commit d40fd02c1faf8faad57a7579b573bc5be51faabe.

Fixes: d40fd02c1faf ("arm64: dts: qcom: sdm845-db845c-navigation-mezzanine: Add cma heap for libcamera softisp support")
Suggested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Link: https://lore.kernel.org/r/20250227-qcom-nonroot-overlays-v2-2-bde44f708cbe@trvn.ru
Signed-off-by: Bjorn Andersson <andersson@kernel.org>