vmlinux.lds.h: Add .symtab, .strtab, and .shstrtab to ELF_DETAILS

When linking vmlinux with LLD, the synthetic sections .symtab, .strtab,
and .shstrtab are listed as orphaned. Add them to the ELF_DETAILS section
so there will be no warnings when --orphan-handling=warn is used more
widely. (They are added above comment as it is the more common
order[1].)

ld.lld: warning: <internal>:(.symtab) is being placed in '.symtab'
ld.lld: warning: <internal>:(.shstrtab) is being placed in '.shstrtab'
ld.lld: warning: <internal>:(.strtab) is being placed in '.strtab'

[1] https://lore.kernel.org/lkml/20200622224928.o2a7jkq33guxfci4@google.com/

Reported-by: Fangrui Song <maskray@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20200821194310.3089815-6-keescook@chromium.org

include/asm-generic/vmlinux.lds.h

@@ -823,7 +823,10 @@
 
 /* Required sections not related to debugging. */
 #define ELF_DETAILS							\
-		.comment 0 : { *(.comment) }
+		.comment 0 : { *(.comment) }				\
+		.symtab 0 : { *(.symtab) }				\
+		.strtab 0 : { *(.strtab) }				\
+		.shstrtab 0 : { *(.shstrtab) }
 
 #ifdef CONFIG_GENERIC_BUG
 #define BUG_TABLE							\