riscv: ptdump: use seq_puts() in pt_dump_seq_puts() macro

The pt_dump_seq_puts() macro incorrectly uses seq_printf() instead of
seq_puts(). This is both a performance issue and conceptually wrong,
as the macro name suggests plain string output (puts) but the
implementation uses formatted output (printf).

The macro is used in ptdump.c:301 to output a newline character. Using
seq_printf() adds unnecessary overhead for format string parsing when
outputting this constant string.

This bug was introduced in commit 59c4da8640cc ("riscv: Add support to
dump the kernel page tables") in 2020, which copied the implementation
pattern from other architectures that had the same bug.

Fixes: 59c4da8640cc ("riscv: Add support to dump the kernel page tables")
Signed-off-by: Josephine Pfeiffer <hi@josie.lol>
Link: https://lore.kernel.org/r/20251018170451.3355496-1-hi@josie.lol
Signed-off-by: Paul Walmsley <pjw@kernel.org>