getrlimit64: fix for 32-bit configurations with default version >= 2.2

Commit 24731685 ("prlimit: Translate old_rlimit from RLIM64_INFINITY to
RLIM_INFINITY") broken the getrlimit64 for 32-bit configurations which
do no need the 2GiB limited compat getrlimit (default version >= 2.2).

This patch fixes that by restoring the weak alias in that case.

Changelog:
	* sysdeps/unix/sysv/linux/getrlimit64 (getrlimit64)
	[!__RLIM_T_MATCHES_RLIM64_T]
	[!SHLIB_COMPAT (libc, GLIBC_2_1, GLIBC_2_2)]: Define as weak alias of
	__getrlimit64. Add libc_hidden_weak.