Don't use sprintf_vma for CORE_ADDR

Don't use sprintf_vma for CORE_ADDR

A few spots in gdb use sprintf_vma to print a CORE_ADDR.  This will
fail on a 32-bit build once CORE_ADDR is always a 64-bit type.

This patch replaces these calls with phex instead.

gdb/ChangeLog
2020-03-12  Tom Tromey  <tom@tromey.com>

	* remote.c (remote_target::download_tracepoint)
	(remote_target::enable_tracepoint)
	(remote_target::disable_tracepoint): Use phex, not sprintf_vma.
	* breakpoint.c (print_recreate_masked_watchpoint): Use phex, not
	sprintf_vma.