uml: fix link error from prefixing of i386 syscalls with ptregs_

Fix the following link error:

arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x11c): undefined reference to `ptregs_fork'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x140): undefined reference to `ptregs_execve'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x2cc): undefined reference to `ptregs_iopl'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x2d8): undefined reference to `ptregs_vm86old'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x2f0): undefined reference to `ptregs_sigreturn'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x2f4): undefined reference to `ptregs_clone'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x3ac): undefined reference to `ptregs_vm86'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x3c8): undefined reference to `ptregs_rt_sigreturn'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x3fc): undefined reference to `ptregs_sigaltstack'
arch/um/sys-i386/built-in.o: In function `sys_call_table':
(.rodata+0x40c): undefined reference to `ptregs_vfork'

This was introduced by commit 253f29a4, "x86: pass in pt_regs pointer
for syscalls that need it"

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jeff Dike <jdike@addtoit.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/sys-i386/sys_call_table.S

@@ -9,6 +9,17 @@
 
 #define old_mmap old_mmap_i386
 
+#define ptregs_fork sys_fork
+#define ptregs_execve sys_execve
+#define ptregs_iopl sys_iopl
+#define ptregs_vm86old sys_vm86old
+#define ptregs_sigreturn sys_sigreturn
+#define ptregs_clone sys_clone
+#define ptregs_vm86 sys_vm86
+#define ptregs_rt_sigreturn sys_rt_sigreturn
+#define ptregs_sigaltstack sys_sigaltstack
+#define ptregs_vfork sys_vfork
+
 .section .rodata,"a"
 
 #include "../../x86/kernel/syscall_table_32.S"