waf: change ChibiOS ld script path back to relative

Fixes #9461

Tools/ardupilotwaf/boards.py

@@ -398,7 +398,7 @@ class chibios(Board):
             '-L%s' % env.BUILDROOT,
             '-L%s' % cfg.srcnode.make_node('modules/ChibiOS/os/common/startup/ARMCMx/compilers/GCC/ld/').abspath(),
             '-L%s' % cfg.srcnode.make_node('libraries/AP_HAL_ChibiOS/hwdef/common/').abspath(),
-            '-Wl,--gc-sections,--no-warn-mismatch,--library-path=/ld,--script=%s/ldscript.ld,--defsym=__process_stack_size__=%s,--defsym=__main_stack_size__=%s' % (cfg.env.BUILDROOT, cfg.env.PROCESS_STACK, cfg.env.MAIN_STACK)
+            '-Wl,--gc-sections,--no-warn-mismatch,--library-path=/ld,--script=ldscript.ld,--defsym=__process_stack_size__=%s,--defsym=__main_stack_size__=%s' % (cfg.env.PROCESS_STACK, cfg.env.MAIN_STACK)
         ]
 
         if cfg.env.DEBUG: