remove use of sprintf_vma in remote_get_tracepoint_status

remove use of sprintf_vma in remote_get_tracepoint_status

This function takes a VMA and was forcing us to perform a cast to
compile without warning on one platform. Except that the cast caused
a warning on sparc-solaris.  This patch fixes the problem by using
phex_nz instead.

gdb/ChangeLog:

        * remote.c (remote_get_tracepoint_status): Delete addrbuf
        local variable.  Avoid use of sprintf_vma.