fix process_madvise build break for arm64

0-day reported build break from process_madvise on ARM64.

   aarch64-linux-ld: arch/arm64/kernel/head.o: relocation R_AARCH64_ABS32 against `_kernel_offset_le_lo32' can not be used when making a shared object
   aarch64-linux-ld: arch/arm64/kernel/efi-entry.stub.o: relocation R_AARCH64_ABS32 against `__efistub_stext_offset' can not be used when making a shared object
   arch/arm64/kernel/head.o: In function `kimage_vaddr':
   (.idmap.text+0x0): dangerous relocation: unsupported relocation
   arch/arm64/kernel/head.o: In function `__primary_switch':
   (.idmap.text+0x378): dangerous relocation: unsupported relocation
   (.idmap.text+0x380): dangerous relocation: unsupported relocation
>> arch/arm64/kernel/sys32.o:(.rodata+0xdb8): undefined reference to `__arm64_process_madvise'

This patch should fix it.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Minchan Kim <[email protected]>
Reported-by: kbuild test robot <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>

arch/arm64/include/asm/unistd32.h

@@ -892,7 +892,7 @@ __SYSCALL(__NR_watch_sb, sys_watch_sb)
 #define __NR_fsinfo 442
 __SYSCALL(__NR_fsinfo, sys_fsinfo)
 #define __NR_process_madvise 443
-__SYSCALL(__NR_process_madvise, process_madvise)
+__SYSCALL(__NR_process_madvise, sys_process_madvise)
 
 /*
  * Please add new compat syscalls above this comment and update