fix(asm): encode RISC-V CALL sym(SB) as JAL

Assisted-by: DeepSeek V4 Pro

asm/goobjriscv.go

@@ -25,17 +25,22 @@ func (img *Image) GOObjectRISCV(pkgPath, srcPath string) ([]byte, error) {
 		return nil, err
 	}
 	return img.emitGOObject(pkgPath, srcPath, pre, 2, func(r Reloc) (uint16, uint8) {
-		if r.Kind == RelRISCVPCRELSType {
+		switch r.Kind {
+		case RelRISCVPCRELSType:
 			return relocRISCVPcrelStype, 8
+		case RelRISCVJal:
+			return relocRISCVJal, 4
+		default:
+			return relocRISCVPcrelItype, 8
 		}
-		return relocRISCVPcrelItype, 8
 	})
 }
 
 // RISC-V relocation types (cmd/internal/objabi).  The Go linker applies
 // R_RISCV_PCREL_ITYPE/STYPE to an AUIPC + I/S-type instruction pair as a
-// single 8-byte field.
+// single 8-byte field; R_RISCV_JAL covers a single 4-byte J-type instruction.
 const (
+	relocRISCVJal        = 59 // R_RISCV_JAL
 	relocRISCVPcrelItype = 62 // R_RISCV_PCREL_ITYPE
 	relocRISCVPcrelStype = 63 // R_RISCV_PCREL_STYPE
 )