[linker] fix linker in no-bootloader mode

This was introduced in 02f71ee4. The sections.ld was being specified
to the linker twice, hence no text sections for data were being created.

Thanks to David Wood for helping me find this hilarious stupidity.

firmware/Makefile

@@ -123,7 +123,7 @@ SYSTEM		+= test/tmain.c
 ifdef BOOTLOADER
 LINKERS		?= chip/$(shell echo $(TARGET_CHIP) | $(TR) A-Z a-z)_bootloader.ld
 else
-LINKERS		?= chip/$(shell echo $(TARGET_CHIP) | $(TR) A-Z a-z).ld chip/sections.ld
+LINKERS		?= chip/$(shell echo $(TARGET_CHIP) | $(TR) A-Z a-z).ld
 endif
 LINKERS		+= chip/sections.ld