firmware: qcom_scm: fix bogous abuse of dma-direct internals

commit 459b1f86 upstream.

As far as the device is concerned the dma address is the physical
address.  There is no need to convert it to a physical address,
especially not using dma-direct internals that are not available
to drivers and which will interact badly with IOMMUs.  Last but not
least the commit introducing it claimed to just fix a type issue,
but actually changed behavior.

Fixes: 6e37ccf7

 ("firmware: qcom_scm: Use proper types for dma mappings")
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200414123136.441454-1-hch@lst.de
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>