cfg.mk: Adjust sc_prohibit_int_ijk to support 'exempt from syntax-check'

There might be cases, like with typed params, where triggering this check isn't
desirable. But including the whole module in the exception regex is not always
to right way of doing things. By adding an option to manually disable this check
on a specific occurrence, the module itself will still be checked against the
rule.

cfg.mk

@@ -572,6 +572,7 @@ sc_prohibit_int_index:
 
 sc_prohibit_int_ijk:
 	@prohibit='\<(int|unsigned) ([^(=]* )*(i|j|k)\>(\s|,|;)'	\
+	exclude='exempt from syntax-check'				\
 	halt='use size_t, not int/unsigned int for loop vars i, j, k'	\
 	  $(_sc_search_regexp)