x86/asm/entry: Move the 'thunk' functions to arch/x86/entry/

These are all calling x86 entry code functions, so move them close
to other entry code.

Change lib-y to obj-y: there's no real difference between the two
as we don't really drop any of them during the linking stage, and
obj-y is the more common approach for core kernel object code.

Cc: Borislav Petkov <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Andy Lutomirski <[e-mail]>
Cc: Denys Vlasenko <[e-mail]>
Cc: Brian Gerst <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/entry/Makefile

···
 #
 # Makefile for the x86 low level entry code
 #
-obj-y				:= entry_$(BITS).o
-
+obj-y				:= entry_$(BITS).o thunk_$(BITS).o
 obj-y				+= vdso/
 
 obj-$(CONFIG_IA32_EMULATION)	+= ia32entry.o

arch/x86/lib/Makefile

···
 obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
 
 lib-y := delay.o misc.o cmdline.o
-lib-y += thunk_$(BITS).o
 lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o

arch/x86/um/Makefile

···
 
 obj-y += syscalls_64.o vdso/
 
-subarch-y = ../lib/csum-partial_64.o ../lib/memcpy_64.o ../lib/thunk_64.o \
+subarch-y = ../lib/csum-partial_64.o ../lib/memcpy_64.o ../entry/thunk_64.o \
 		../lib/rwsem.o
 
 endif