ARM: disallow pre-ARMv5 builds with ld.lld

lld cannot build for ARMv4/v4T targets because it inserts 'blx' instructions
that are unsupported there:

  ld.lld: warning: lld uses blx instruction, no object with architecture supporting feature detected

Add a Kconfig time dependency to prevent those targets from being
selected in randconfig builds.

Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
Link: llvm/llvm-project#50764
Link: ClangBuiltLinux#964
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnd Bergmann <[email protected]>

Author: arndb

arch/arm/Kconfig

@@ -342,12 +342,14 @@ comment "CPU Core family selection"
 config ARCH_MULTI_V4
 	bool "ARMv4 based platforms (FA526, StrongARM)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_FA526 if !(CPU_SA110 || CPU_SA1100)
 
 config ARCH_MULTI_V4T
 	bool "ARMv4T based platforms (ARM720T, ARM920T, ...)"
 	depends on !ARCH_MULTI_V6_V7
+	depends on !LD_IS_LLD
 	select ARCH_MULTI_V4_V5
 	select CPU_ARM920T if !(CPU_ARM7TDMI || CPU_ARM720T || \
 		CPU_ARM740T || CPU_ARM9TDMI || CPU_ARM922T || \