[riscv] Place .got and .got.plt in .data

Even though we build with -mno-plt, redundant .got and .got.plt
sections are still generated.

Include these redundant sections within .data (which has identical
section attributes) to simplify the section list.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/riscv/scripts/sbi.lds

@@ -51,6 +51,8 @@ SECTIONS {
 	KEEP(*(SORT(.tbl.*)))	/* Various tables.  See include/tables.h */
 	KEEP(*(.provided))
 	KEEP(*(.provided.*))
+	*(.got)
+	*(.got.plt)
 	_edata = .;
     }