Fix: target discovery logic in stm32l4 #2942

Job	Run time
build-msvc (meson, windows-2022)	1m 34s
build-linux (jammy, 96b_carbon)	43s
build-macos (macos-13)	38s
build-linux (jammy, blackpill-f401cc)	30s
build-macos (macos-13, gcc@11)	1m 17s
build-macos (macos-14)	21s
build-macos (macos-13, gcc@12)	1m 11s
build-linux (jammy, blackpill-f401ce)	43s
build-macos (macos-latest)	21s
build-macos (macos-13, gcc@13)	59s
build-linux (jammy, blackpill-f411ce)	35s
build-mingw (windows-2022, mingw64)	1m 35s
build-macos (macos-13, gcc@14)	1m 13s
build-linux (jammy, bluepill)	33s
build-mingw (windows-2022, ucrt64)	2m 7s
build-macos (macos-14, gcc@11)	37s
build-linux (jammy, ctxlink)	49s
build-mingw (windows-2022, clang64)	1m 40s
build-macos (macos-14, gcc@12)	41s
build-linux (jammy, f072)	1m 7s
build-macos (macos-14, gcc@13)	42s
size-diff	41s
build-linux (jammy, f3)	46s
build-macos (macos-14, gcc@14)	34s
build-linux (jammy, f4discovery)	1m 12s
build-linux (jammy, hydrabus)	39s
build-linux (jammy, launchpad-icdi)	35s
build-linux (jammy, native)	38s
build-linux (jammy, native-uncommon)	37s
build-linux (jammy, native-st-clones)	1m 46s
build-linux (jammy, native-riscv)	1m 1s
build-linux (jammy, native-remote)	37s
build-linux (jammy, stlink)	31s
build-linux (jammy, stlinkv3)	32s
build-linux (jammy, swlink)	31s
	30m 36s

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