llext: export symbols, needed for aria #19962

Job	Run time
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	7m 26s
build-linux (mnfst, mtl lnl)	5m 49s
build-linux (mnfst, ptl)	5m 45s
LP64-WIP	4m 4s
build-linux (mnfst, tgl tgl-h)	6m 14s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	6m 43s
build-linux (zmain, mtl lnl)	5m 57s
manifest-check	55s
build-linux (zmain, ptl)	4m 42s
build-windows (imx8 imx8x imx8m imx8ulp)	8m 21s
build-linux (zmain, tgl tgl-h)	5m 27s
build-windows (mtl lnl)	8m 0s
build-windows (ptl)	6m 38s
build-linux (-d, mnfst, lnl)	4m 41s
build-windows (tgl tgl-h)	6m 59s
build-linux (mnfst, --all)	14m 25s
build-windows (-d, lnl)	6m 23s
compare-linux-win	36s
	1h 49m 5s

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