Linux: Add oddly-named arm syscalls to syscall-names.list

<asm/unistd.h> on arm defines the following macros:

#define __ARM_NR_breakpoint             (__ARM_NR_BASE+1)
#define __ARM_NR_cacheflush             (__ARM_NR_BASE+2)
#define __ARM_NR_usr26                  (__ARM_NR_BASE+3)
#define __ARM_NR_usr32                  (__ARM_NR_BASE+4)
#define __ARM_NR_set_tls                (__ARM_NR_BASE+5)
#define __ARM_NR_get_tls                (__ARM_NR_BASE+6)

These do not follow the regular __NR_* naming convention and
have so far been ignored by the syscall-names.list consistency
checks.  This commit adds these names to the file, preparing
for the availability of these names in the regular __NR_*
namespace.