sparc64: Fix buggy strlcpy() conversion in ldom_reboot().

Commit 117a0c5f ("sparc: kernel: using
strlcpy() instead of strcpy()") added a bug to ldom_reboot in
arch/sparc/kernel/ds.c

-		strcpy(full_boot_str + strlen("boot "), boot_command);
+				     strlcpy(full_boot_str + strlen("boot "), boot_command,
+				     			     sizeof(full_boot_str + strlen("boot ")));

That last sizeof() expression evaluates to sizeof(size_t) which is
not what was intended.

Also even the corrected:

     sizeof(full_boot_str) + strlen("boot ")

is not right as the destination buffer length is just plain
"sizeof(full_boot_str)" and that's what the final argument
should be.

Signed-off-by: David S. Miller <davem@davemloft.net>