Revert "ipmi_si: fix memory leak on new_smi"

This reverts commit c97e410, which
incorrectly was taken from upstream c0a32fe.

The referenced memory leak doesn't exist on the 4.14 stable branch as
the new logic of doing the kzalloc hasn't moved to this function.
By adding this kfree we actually end up doing double kfree as all callers of
smi_add does a kfree on error.

Sample with SLAB_FREELIST_HARDENED=y:

ipmi_si: Adding ACPI-specified kcs state machine
IPMI System Interface driver.
ipmi_si: probing via SPMI
ipmi_si: SPMI: io 0xca2 regsize 1 spacing 1 irq 0
(NULL device *): SPMI-specified kcs state machine: duplicate
------------[ cut here ]------------
kernel BUG at mm/slub.c:295!
invalid opcode: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.8-gentoo-r1 #5
Hardware name: Supermicro X9SCL/X9SCM/X9SCL/X9SCM, BIOS 2.2 02/20/2015
task: ffff88080c208000 task.stack: ffffc90000020000
RIP: 0010:kfree+0xf5/0x157
RSP: 0000:ffffc90000023e58 EFLAGS: 00010246
RAX: ffff88080b2e6200 RBX: ffff88080b2e6200 RCX: ffff88080b2e6200
RDX: 000000000000008e RSI: ffff88082fc1cd60 RDI: ffff88080c003080
RBP: ffffc90000002808 R08: 000000000001cd60 R09: ffffffff814da10e
R10: ffffea00202cb980 R11: 000000000000005c R12: ffffffff814da10e
R13: 00000000ffffffed R14: ffffffff82317bd0 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff88082fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000002e09001 CR4: 00000000001606f0
Call Trace:
 init_ipmi_si+0x493/0x5c7
 ? cleanup_ipmi_si+0x84/0x84
 ? set_debug_rodata+0xc/0xc
 ? kthread+0x4c/0x11c
 do_one_initcall+0x94/0x13d
 ? set_debug_rodata+0xc/0xc
 kernel_init_freeable+0x112/0x18e
 ? rest_init+0xa0/0xa0
 kernel_init+0x5/0xe1
 ret_from_fork+0x22/0x30
Code: 24 18 49 8b 7a 30 48 8b 37 65 48 8b 56 08 65 48 03 35 3a 29 e2 7e 4c 3b 56 10 75 39 48 8b 0e 48 63 47 20 48 01 d8 48 39 cb 75 02 <0f> 0b 49 89 c0 4c 33
 87 40 01 00 00 4c 31 c1 48 89 08 48 8d 4a
---[ end trace 4ac2e2c100842676 ]---

Signed-off-by: John Einar Reitan <john.einar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/ipmi/ipmi_si_intf.c

@@ -3469,7 +3469,6 @@ static int add_smi(struct smi_info *new_smi)
 				 ipmi_addr_src_to_str(new_smi->addr_source),
 				 si_to_str[new_smi->si_type]);
 			rv = -EBUSY;
-			kfree(new_smi);
 			goto out_err;
 		}
 	}