spi: tegra210-quad: Protect curr_xfer clearing in tegra_qspi_non_combined_seq_xfer

spi: tegra210-quad: Protect curr_xfer clearing in tegra_qspi_non_combined_seq_xfer

Protect the curr_xfer clearing in tegra_qspi_non_combined_seq_xfer()
with the spinlock to prevent a race with the interrupt handler that
reads this field to check if a transfer is in progress.

Fixes: b4e002d8a7ce ("spi: tegra210-quad: Fix timeout handling")
Signed-off-by: Breno Leitao <leitao@debian.org>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20260126-tegra_xfer-v2-5-6d2115e4f387@debian.org
Signed-off-by: Mark Brown <broonie@kernel.org>