x86: Move bootstrap code and linker script to cpu/x86

This is a refactoring patch, no functionality is changed. It moves
loader.S and galileo.ld from platform/galileo/ to cpu/x86/ directory
since they seem to be more SoC-specific than platform-specific.

It also renames galileo.ld to quarkX1000.ld since it can be used by
any platform based on Quark X1000 SoC, not only Galileo.

Furthermore, this patch also renames loader.S to bootstrap_quarkX1000.S
since it is pretty much a bootstrap code to any platform based on Quark
X1000 SoC.

cpu/x86/Makefile.x86_quarkX1000

@@ -2,4 +2,6 @@ include $(CONTIKI)/cpu/x86/Makefile.x86_common
 
 CONTIKI_CPU_DIRS += drivers/legacy_pc init/legacy_pc
 
-CONTIKI_SOURCEFILES += rtc.c pit.c pic.c irq.c
+CONTIKI_SOURCEFILES += bootstrap_quarkX1000.S rtc.c pit.c pic.c irq.c
+
+LINKERSCRIPT = $(CONTIKI)/cpu/x86/quarkX1000.ld

platform/galileo/Makefile.galileo

@@ -3,9 +3,7 @@ LIBGCC_PATH = /usr/lib/gcc/$(shell gcc -dumpmachine)/$(shell gcc -dumpversion)
 
 CONTIKI_TARGET_DIRS = . core/sys/
 CONTIKI_TARGET_MAIN = ${addprefix $(OBJECTDIR)/,contiki-main.o}
-CONTIKI_SOURCEFILES += contiki-main.c newlib-syscalls.c loader.S clock.c rtimer-arch.c
-
-LINKERSCRIPT = $(CONTIKI)/platform/galileo/galileo.ld
+CONTIKI_SOURCEFILES += contiki-main.c newlib-syscalls.c clock.c rtimer-arch.c
 
 CONTIKI_CPU=$(CONTIKI)/cpu/x86
 include $(CONTIKI)/cpu/x86/Makefile.x86_quarkX1000