proc-cmdline: introduce PROC_CMDLINE_RD_STRICT

Our current set of flags allows an option to be either
use just in initrd or both in initrd and normal system.
This new flag is intended to be used in the case where
you want apply some settings just in initrd or just
in normal system.

src/basic/proc-cmdline.c

@@ -66,7 +66,8 @@ int proc_cmdline_parse_given(const char *line, proc_cmdline_parse_t parse_item,
 
                         if (flags & PROC_CMDLINE_STRIP_RD_PREFIX)
                                 key = q;
-                }
+                } else if (in_initrd() && flags & PROC_CMDLINE_RD_STRICT)
+                        continue;
 
                 value = strchr(key, '=');
                 if (value)

src/basic/proc-cmdline.h

@@ -8,6 +8,7 @@
 enum {
         PROC_CMDLINE_STRIP_RD_PREFIX = 1,
         PROC_CMDLINE_VALUE_OPTIONAL = 2,
+        PROC_CMDLINE_RD_STRICT = 4
 };
 
 typedef int (*proc_cmdline_parse_t)(const char *key, const char *value, void *data);