boards: nordic: bm_nrf54l15dk: sram adjustments

[eivindj-nordic]

Adjust sram sizes to not overlap with Viper context.

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[nordicjm]

from what I remember the idea of BM was users would not be using flpr, and if they do they would need to do that entirely themselves (i.e. in their own boards) - so has that changed?

[bjorn-tore-taraldsen]

from what I remember the idea of BM was users would not be using flpr, and if they do they would need to do that entirely themselves (i.e. in their own boards) - so has that changed?

You are right that we do not have a plan of supporting VPR (flpr) in BM (as of now), and that hasn't changed.
I assume you are asking this based on how we have done SRAM partitioning?
But with nRF54LV10 and nRF54LM20A included, that have both VPR Context and Protected RAM in this area, and that we have to exclude Protected RAM. I decided to do it equally on all boards, not include any of these partitions in the common SRAM. (Ref PR #621)