seq_file: Optimize seq_puts()

Most of seq_puts() usages are done with a string literal. In such cases,
the length of the string car be computed at compile time in order to save
a strlen() call at run-time. seq_putc() or seq_write() can then be used
instead.

This saves a few cycles.

To have an estimation of how often this optimization triggers:
   $ git grep seq_puts.*\" | wc -l
   3436

   $ git grep seq_puts.*\".\" | wc -l
   84

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/a8589bffe4830dafcb9111e22acf06603fea7132.1713781332.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Christian Brauner <brauner@kernel.org>
The output for seq_putc() generation has also be checked and works.