We weren't using SYSCALL_DEFINE for sys_switch_endian(), which means
it wasn't able to be traced by CONFIG_FTRACE_SYSCALLS.
By using the macro we create the right metadata and the syscall is
visible. eg:
# cd /sys/kernel/debug/tracing
# echo 1 | tee events/syscalls/sys_*_switch_endian/enable
# ~/switch_endian_test
# cat trace
...
switch_endian_t-3604 [009] .... 315.175164: sys_switch_endian()
switch_endian_t-3604 [009] .... 315.175167: sys_switch_endian -> 0x5555aaaa5555aaaa
switch_endian_t-3604 [009] .... 315.175169: sys_switch_endian()
switch_endian_t-3604 [009] .... 315.175169: sys_switch_endian -> 0x5555aaaa5555aaaa
Fixes: 529d235a0e ("powerpc: Add a proper syscall for switching endianness")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
81dac81778