arch: x86: Fix x86 linking

Summary:
- I noticed that qemu-i486:nsh can not start
- Finally, I found that the issue was introduced by 4910d43
- Actually, nuttx_elf was linked dynamically
- This commit fixes this issue

Impact:
- Affects x86 (32bit) only

Testing:
- Tested with qemu-i486:nsh

arch/x86/src/Makefile

@@ -74,7 +74,7 @@ OBJS = $(AOBJS) $(COBJS)
 
 LDSTARTGROUP ?= --start-group
 LDENDGROUP ?= --end-group
-LDFLAGS += $(ARCHSCRIPT)
+LDFLAGS += $(ARCHSCRIPT) -static
 
 BOARDMAKE = $(if $(wildcard board$(DELIM)Makefile),y,)