Add .sdata section to linker script

riscv-rt/link.x

@@ -58,6 +58,7 @@ SECTIONS
     _sdata = .;
     /* Must be called __global_pointer$ for linker relaxations to work. */
     PROVIDE(__global_pointer$ = . + 0x800);
+    *(.sdata .sdata.*);
     *(.data .data.*);
     . = ALIGN(4);
     _edata = .;