Fix SPARC64 handling of R_SPARC_H34 (bug 24231).

Fix SPARC64 handling of R_SPARC_H34 (bug 24231).

Building glibc with -Wextra shows a -Wimplicit-fallthrough warning for
SPARC64 that appears to be a real bug in glibc.  The dynamic linker
handling of R_SPARC_H34 falls through to that of R_SPARC_H44, which in
the case of this code is nonsensical (it means the value computed for
R_SPARC_H34 gets overwritten by one computed with the different logic
for R_SPARC_H44).  Thus, this patch adds the missing break there.
Note: I do not have a testcase to demonstrate this bug.

Tested with build-many-glibcs.py.

	[BZ #24231]
	* sysdeps/sparc/sparc64/dl-machine.h (elf_machine_rela): Add break
	after R_SPARC_H34 case.