vmlinux.lds.h: catch UBSAN's "unnamed data" into data

When building kernel with both LD_DEAD_CODE_DATA_ELIMINATION and
UBSAN, LLVM stack generates lots of "unnamed data" sections:

ld.lld: warning: net/built-in.a(netfilter/utils.o): (.data.$__unnamed_2)
is being placed in '.data.$__unnamed_2'
ld.lld: warning: net/built-in.a(netfilter/utils.o): (.data.$__unnamed_3)
is being placed in '.data.$__unnamed_3'
ld.lld: warning: net/built-in.a(netfilter/utils.o): (.data.$__unnamed_4)
is being placed in '.data.$__unnamed_4'
ld.lld: warning: net/built-in.a(netfilter/utils.o): (.data.$__unnamed_5)
is being placed in '.data.$__unnamed_5'

[...]

Also handle this by adding the related sections to generic definitions.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>