nvmem: qfprom: use NVMEM_DEVID_AUTO for multiple instances

There could be multiple qfprom devices on some SoCs.  For example, on
MSM8939, qfprom@58000 holds efuse bits for Core Power Reduction (CPR),
and qfprom@5c000 holds bits for TSENS.  Registering multiple nvmem
devices with the same id results in the following failure on the second
device.

[    1.682731] sysfs: cannot create duplicate filename /bus/nvmem/devices/qfprom0
[    1.685889] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.107-00567-g11c887ce2838-dirty #334
[    1.693191] Hardware name: Square, Inc. T2 Devkit (DT)
[    1.701610] Call trace:
[    1.706673]  dump_backtrace+0x0/0x158
[    1.708987]  show_stack+0x14/0x20
[    1.712810]  dump_stack+0x98/0xbc
[    1.716114]  sysfs_warn_dup+0x60/0x78
[    1.719401]  sysfs_do_create_link_sd.isra.0+0xdc/0xe8
[    1.723047]  sysfs_create_link+0x20/0x40
[    1.728088]  bus_add_device+0x68/0x130
[    1.732083]  device_add+0x3f8/0x628
[    1.735639]  nvmem_register.part.4+0x150/0x348
[    1.739018]  devm_nvmem_register+0x4c/0xa8
[    1.743532]  qfprom_probe+0x94/0xb8
[    1.747615]  platform_drv_probe+0x50/0xa0
[    1.750998]  really_probe+0x1b8/0x298
[    1.755164]  driver_probe_device+0x58/0x100
[    1.758810]  __driver_attach+0xe0/0xe8
[    1.762802]  bus_for_each_dev+0x74/0xc8
[    1.766622]  driver_attach+0x20/0x28
[    1.770354]  bus_add_driver+0x1ac/0x218
[    1.774175]  driver_register+0x60/0x110
[    1.777734]  __platform_driver_register+0x40/0x48
[    1.781570]  qfprom_driver_init+0x18/0x20
[    1.786416]  do_one_initcall+0x5c/0x178
[    1.790418]  kernel_init_freeable+0x198/0x244
[    1.794062]  kernel_init+0x10/0x108
[    1.798567]  ret_from_fork+0x10/0x18
[    1.802084] qcom,qfprom: probe of 5c000.qfprom failed with error -17

Fix this issue by using NVMEM_DEVID_AUTO.
Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-9-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/qfprom.c

@@ -31,6 +31,7 @@ static struct nvmem_config econfig = {
 	.name = "qfprom",
 	.stride = 1,
 	.word_size = 1,
+	.id = NVMEM_DEVID_AUTO,
 	.reg_read = qfprom_reg_read,
 };