misc: fastrpc: free dma buf scatter list

dma buf scatter list is never freed, free it!

Orignally detected by kmemleak:
backtrace:
[<ffffff80088b7658>] kmemleak_alloc+0x50/0x84
[<ffffff8008373284>] sg_kmalloc+0x38/0x60
[<ffffff8008373144>] __sg_alloc_table+0x60/0x110
[<ffffff800837321c>] sg_alloc_table+0x28/0x58
[<ffffff800837336c>] __sg_alloc_table_from_pages+0xc0/0x1ac
[<ffffff800837346c>] sg_alloc_table_from_pages+0x14/0x1c
[<ffffff8008097a3c>] __iommu_get_sgtable+0x5c/0x8c
[<ffffff800850a1d0>] fastrpc_dma_buf_attach+0x84/0xf8
[<ffffff80085114bc>] dma_buf_attach+0x70/0xc8
[<ffffff8008509efc>] fastrpc_map_create+0xf8/0x1e8
[<ffffff80085086f4>] fastrpc_device_ioctl+0x508/0x900
[<ffffff80082428c8>] compat_SyS_ioctl+0x128/0x200
[<ffffff80080832c4>] el0_svc_naked+0x34/0x38
[<ffffffffffffffff>] 0xffffffffffffffff

Reported-by: Mayank Chopra <[e-mail]>
Signed-off-by: Srinivas Kandagatla <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/fastrpc.c

···
 	mutex_lock(&buffer->lock);
 	list_del(&a->node);
 	mutex_unlock(&buffer->lock);
+	sg_free_table(&a->sgt);
 	kfree(a);
 }