LLEXT: update for new Zephyr paths #17155

Job	Run time
build-linux (mnfst, imx8 imx8x imx8m imx8ulp)	5m 38s
build-windows (imx8 imx8x imx8m imx8ulp)	7m 32s
build-windows (mtl)	6m 11s
build-linux (mnfst, mtl)	4m 59s
build-windows (tgl tgl-h)	7m 54s
build-linux (mnfst, lnl)	4m 32s
build-windows (-d, mtl)	6m 53s
build-linux (mnfst, tgl tgl-h)	5m 32s
build-linux (zmain, imx8 imx8x imx8m imx8ulp)	5m 7s
build-linux (zmain, mtl)	4m 31s
LP64-WIP	3m 58s
build-linux (zmain, lnl)	4m 21s
build-linux (zmain, tgl tgl-h)	5m 29s
manifest-check	42s
build-linux (-d, mnfst, mtl)	4m 57s
compare-linux-win	32s
	1h 18m 48s

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