Check os_snprintf() result more consistently - maximum length

Check os_snprintf() result more consistently - maximum length

This adds verification of os_snprintf() result against the maximum
buffer length. These changes were done automatically with spatch
using the following semantic patch:

@@
expression E1,E2,E3;
statement S1;
@@

  E1 = os_snprintf(E2, E3, ...);
- if (\( E1 < 0 \| E1 <= 0 \))
+ if (os_snprintf_error(E3, E1))
(
  S1
|
{ ... }
)

Signed-off-by: Jouni Malinen <j@w1.fi>