NuttX: update submodule to branch px4_firmware_nuttx-10.3.0+ with "FlexSPI allow RWW" merged

[MaEtUgR]

Solved Problem

When updating my local main branch I got:

$ git submodule update --init --recursive
fatal: transport 'file' not allowed
fatal: Fetched in submodule path 'platforms/nuttx/NuttX/nuttx', but it did not contain 4c875d0fdffb4f9ba0e0e341ae567d4d0a544e46. Direct fetching of that commit failed.

I tracked it down to #24158 which was merging a reference to the NuttX pr branch of PX4/NuttX#327 before it was merged. But after it was merged the commit hash changed.
4c875d0fdffb4f9ba0e0e341ae567d4d0a544e46 -> 9a213327fbb2dab252185d468fb29348e1833d8c

Solution

Switch to the commit with the same content but different hash after it was merged because that one is in the branch https://github.com/PX4/NuttX/tree/px4_firmware_nuttx-10.3.0%2B and hence advertised by GitHub/git.

Changelog Entry

Fix NuttX submodule reference

Test coverage

This checks the submodules out cleanly again for me.

Context