wifi: ath11k: fix deinitialization of firmware resources

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

wifi: ath11k: fix deinitialization of firmware resources

Currently, in ath11k_ahb_fw_resources_init(), iommu domain

mapping is done only for the chipsets having fixed firmware

memory. Also, for such chipsets, mapping is done only if it

does not have TrustZone support.

During deinitialization, only if TrustZone support is not there,

iommu is unmapped back. However, for non fixed firmware memory

chipsets, TrustZone support is not there and this makes the

condition check to true and it tries to unmap the memory which

was not mapped during initialization.

This leads to the following trace -

[ 83.198790] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008

[ 83.259537] Modules linked in: ath11k_ahb ath11k qmi_helpers

.. snip ..

[ 83.280286] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)

[ 83.287228] pc : __iommu_unmap+0x30/0x140

[ 83.293907] lr : iommu_unmap+0x5c/0xa4

[ 83.298072] sp : ffff80000b3abad0

.. snip ..

[ 83.369175] Call trace:

[ 83.376282] __iommu_unmap+0x30/0x140

[ 83.378541] iommu_unmap+0x5c/0xa4

[ 83.382360] ath11k_ahb_fw_resource_deinit.part.12+0x2c/0xac [ath11k_ahb]

[ 83.385666] ath11k_ahb_free_resources+0x140/0x17c [ath11k_ahb]

[ 83.392521] ath11k_ahb_shutdown+0x34/0x40 [ath11k_ahb]

[ 83.398248] platform_shutdown+0x20/0x2c

[ 83.403455] device_shutdown+0x16c/0x1c4

[ 83.407621] kernel_restart_prepare+0x34/0x3c

[ 83.411529] kernel_restart+0x14/0x74

[ 83.415781] __do_sys_reboot+0x1c4/0x22c

[ 83.419427] __arm64_sys_reboot+0x1c/0x24

[ 83.423420] invoke_syscall+0x44/0xfc

[ 83.427326] el0_svc_common.constprop.3+0xac/0xe8

[ 83.430974] do_el0_svc+0xa0/0xa8

[ 83.435659] el0_svc+0x1c/0x44

[ 83.438957] el0t_64_sync_handler+0x60/0x144

[ 83.441910] el0t_64_sync+0x15c/0x160

[ 83.446343] Code: aa0103f4 f9400001 f90027a1 d2800001 (f94006a0)

[ 83.449903] ---[ end trace 0000000000000000 ]---

This can be reproduced by probing an AHB chipset which is not

having a fixed memory region. During reboot (or rmmod) trace

can be seen.

Fix this issue by adding a condition check on firmware fixed memory

hw_param as done in the counter initialization function.

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1