riscv/kexec_file: Fix comment in purgatory relocator

Apparently sec_base doesn't mean relocated symbol value, which seems a
copy-pasting error in the comment. Assigned with the address of section
indexed by sym->st_shndx, it should represent base address of the
relevant section. Let's fix the comment to avoid possible confusion.

Fixes: 838b3e2 ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20250326073450.57648-2-ziyao@disroot.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

Author: ziyao233

arch/riscv/kernel/elf_kexec.c

@@ -390,7 +390,7 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 		const Elf_Sym *sym;	/* symbol to relocate */
 		unsigned long addr;	/* final location after relocation */
 		unsigned long val;	/* relocated symbol value */
-		unsigned long sec_base;	/* relocated symbol value */
+		unsigned long sec_base;	/* relocated section base address */
 		void *loc;		/* tmp location to modify */
 
 		sym = (void *)pi->ehdr + symtab->sh_offset;