soc: imx8m: Probe the SoC driver as platform driver

In the Linux kernel, the following vulnerability has been resolved:

soc: imx8m: Probe the SoC driver as platform driver

With driver_async_probe=* on kernel command line, the following trace is

produced because on i.MX8M Plus hardware because the soc-imx8m.c driver

calls of_clk_get_by_name() which returns -EPROBE_DEFER because the clock

driver is not yet probed. This was not detected during regular testing

without driver_async_probe.

Convert the SoC code to platform driver and instantiate a platform device

in its current device_initcall() to probe the platform driver. Rework

.soc_revision callback to always return valid error code and return SoC

revision via parameter. This way, if anything in the .soc_revision callback

return -EPROBE_DEFER, it gets propagated to .probe and the .probe will get

retried later.

"

------------[ cut here ]------------

WARNING: CPU: 1 PID: 1 at drivers/soc/imx/soc-imx8m.c:115 imx8mm_soc_revision+0xdc/0x180

CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.11.0-next-20240924-00002-g2062bb554dea #603

Hardware name: DH electronics i.MX8M Plus DHCOM Premium Developer Kit (3) (DT)

pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)

pc : imx8mm_soc_revision+0xdc/0x180

lr : imx8mm_soc_revision+0xd0/0x180

sp : ffff8000821fbcc0

x29: ffff8000821fbce0 x28: 0000000000000000 x27: ffff800081810120

x26: ffff8000818a9970 x25: 0000000000000006 x24: 0000000000824311

x23: ffff8000817f42c8 x22: ffff0000df8be210 x21: fffffffffffffdfb

x20: ffff800082780000 x19: 0000000000000001 x18: ffffffffffffffff

x17: ffff800081fff418 x16: ffff8000823e1000 x15: ffff0000c03b65e8

x14: ffff0000c00051b0 x13: ffff800082790000 x12: 0000000000000801

x11: ffff80008278ffff x10: ffff80008209d3a6 x9 : ffff80008062e95c

x8 : ffff8000821fb9a0 x7 : 0000000000000000 x6 : 00000000000080e3

x5 : ffff0000df8c03d8 x4 : 0000000000000000 x3 : 0000000000000000

x2 : 0000000000000000 x1 : fffffffffffffdfb x0 : fffffffffffffdfb

Call trace:

imx8mm_soc_revision+0xdc/0x180

imx8_soc_init+0xb0/0x1e0

do_one_initcall+0x94/0x1a8

kernel_init_freeable+0x240/0x2a8

kernel_init+0x28/0x140

ret_from_fork+0x10/0x20

---[ end trace 0000000000000000 ]---

SoC: i.MX8MP revision 1.1

"