seq_buf: Mark binary printing functions with __printf() attribute

seq_buf: Mark binary printing functions with __printf() attribute

Binary printing functions are using printf() type of format, and compiler
is not happy about them as is:

lib/seq_buf.c:162:17: error: function ‘seq_buf_bprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]

Fix the compilation errors by adding __printf() attribute.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250321144822.324050-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>