Fix error check on default_check() helper function

Fix error check on default_check() helper function

default_check() can return a zero value to indicate an internal error in
one condition for the PRE_CTRL_STR_TO_PARAMS state. This state can be
reached from the default_fixup_args() function which does not check for
a zero value. All other callers of default_check() in that file do check
for a zero return value. Fix it by changing the check to <= 0.

CLA: trivial

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20175)