Use the correct names for the __ARM_NR_* syscalls.

This lets us move all the ARM syscall stubs over to the kernel <asm/unistd.h>.
Our generated <sys/linux-syscalls.h> is now unused, but I'll remove that in a
later change.

Change-Id: Ie5ff2cc4abce1938576af7cbaef615a79c7f310d
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index ff4874e..bf56ffe 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -311,8 +311,8 @@
 int     eventfd:eventfd2(unsigned int, int)  356,328,325
 
 # ARM-specific ARM_NR_BASE == 0x0f0000 == 983040
-int     __set_tls:ARM_set_tls(void*)                                 983045,-1,-1
-int     cacheflush:ARM_cacheflush(long start, long end, long flags)  983042,-1,-1
+int     __set_tls:__ARM_NR_set_tls(void*)                                 983045,-1,-1
+int     cacheflush:__ARM_NR_cacheflush(long start, long end, long flags)  983042,-1,-1
 
 # MIPS-specific
 int	_flush_cache:cacheflush(char *addr, const int nbytes, const int op)	-1,-1,147