lib/vsprintf: Unify FORMAT_STATE_NUM handlers

lib/vsprintf: Unify FORMAT_STATE_NUM handlers

We have two almost identical pieces that handle FORMAT_STATE_NUM case.
The differences are:
- redundant {} for one-line if-else conditional
- missing blank line after variable definitions
- inverted conditional

Unify the style of two.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://patch.msgid.link/20251120083140.3478507-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>