sys: ELF: Rename SHN_FBSD_CACHED => SHN_FREEBSD_CACHED

All other FreeBSD-specific constants have FREEBSD fully spelled out in
their names.  Be consistent.

No functional change (intended).

Reviewed by:    kib
Sponsored by:   The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D55224

sys/kern/link_elf_obj.c

@@ -1716,7 +1716,7 @@ elf_obj_cleanup_globals_cache(elf_file_t ef)
 
 	for (i = 0; i < ef->ddbsymcnt; i++) {
 		sym = ef->ddbsymtab + i;
-		if (sym->st_shndx == SHN_FBSD_CACHED) {
+		if (sym->st_shndx == SHN_FREEBSD_CACHED) {
 			sym->st_shndx = SHN_UNDEF;
 			sym->st_value = 0;
 		}
@@ -1785,7 +1785,7 @@ elf_obj_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res)
 		 * above.
 		 */
 		if (res1 != 0) {
-			sym->st_shndx = SHN_FBSD_CACHED;
+			sym->st_shndx = SHN_FREEBSD_CACHED;
 			sym->st_value = res1;
 			*res = res1;
 			return (0);

sys/sys/elf_common.h

@@ -419,7 +419,8 @@ typedef struct {
 #define	SHN_LOPROC	0xff00		/* First processor-specific. */
 #define	SHN_HIPROC	0xff1f		/* Last processor-specific. */
 #define	SHN_LOOS	0xff20		/* First operating system-specific. */
-#define	SHN_FBSD_CACHED	SHN_LOOS	/* Transient, for sys/kern/link_elf_obj
+#define	SHN_FREEBSD_CACHED	SHN_LOOS
+					/* Transient, for sys/kern/link_elf_obj
 					   linker only: Cached global in local
 					   symtab. */
 #define	SHN_HIOS	0xff3f		/* Last operating system-specific. */