Add QSPI DT node and qspi_opp_table for SC7280 SoC.

Move qspi_opp_table to / because SPI nodes assume
any child node is a spi device and so we can't put the
table underneath the spi controller.
Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
Signed-off-by: Rajesh Patil <rajpat@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1632399378-12229-3-git-send-email-rajpat@codeaurora.org