UPSTREAM: mmc: core: Avoid negative index with array access

Commit 4d0c8d0a ("mmc: core: Use mrq.sbc in close-ended ffu") assigns
prev_idata = idatas[i - 1], but doesn't check that the iterator i is
greater than zero. Let's fix this by adding a check.

Bug: 348419491
Fixes: 4d0c8d0a ("mmc: core: Use mrq.sbc in close-ended ffu")
Link: https://lore.kernel.org/all/20231129092535.3278-1-avri.altman@wdc.com/


Cc: stable@vger.kernel.org
Signed-off-by: Mikko Rapeli <mikko.rapeli@linaro.org>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20240313133744.2405325-2-mikko.rapeli@linaro.org


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: yenchia.chen <yenchia.chen@mediatek.com>
(cherry picked from commit cf55a7ac)
Bug: 345591090
(cherry picked from https://android-review.googlesource.com/q/commit:7869fec72dd3ef450da37f975a933e5c8a5c1281)
Merged-In: I52c750e0a5c182e71b973a2c7e6b027c3da4fbb1
Change-Id: I52c750e0a5c182e71b973a2c7e6b027c3da4fbb1