arm: Use internal symbol for _dl_argv on _dl_start_user

The lld does not support R_ARM_GOTOFF32 to preemptible symbol (_dl_argv
has default visibility).  Use the internal alias instead (one option
would to use HIDDEN_JUMPTARGET, bu the macro is not defined for
!__ASSEMBLER__ and I made this patch arm-specific to avoid require to
check extensivelly on other architecture it this might break something).

Checked on arm-linux-gnueabihf.

Reviewed-by: Fangrui Song <maskray@google.com>