make brace placement in public header struct definitions consistent

placing the opening brace on the same line as the struct keyword/tag
is the style I prefer and seems to be the prevailing practice in more
recent additions.

these changes were generated by the command:

find include/ arch/*/bits -name '*.h' \
-exec sed -i '/^struct [^;{]*$/{N;s/\n/ /;}' {} +

and subsequently checked by hand to ensure that the regex did not pick
up any false positives.

include/sys/procfs.h

@@ -33,8 +33,7 @@ struct elf_prstatus {
 
 #define ELF_PRARGSZ 80
 
-struct elf_prpsinfo
-{
+struct elf_prpsinfo {
 	char pr_state;
 	char pr_sname;
 	char pr_zomb;