wifi: ath11k: add firmware-2.bin support

Firmware IE containers can dynamically provide various information
what firmware supports. Also it can embed more than one image so
updating firmware is easy, user just needs to update one file in
/lib/firmware/.

The firmware API 2 or higher will use the IE container format, the
current API 1 will not use the new format but it still is supported
for some time. Firmware API 2 files are named as firmware-2.bin
(which contains both amss.bin and m3.bin images) and API 1 files are
amss.bin and m3.bin.

Currently ath11k PCI driver provides firmware binary (amss.bin) path to
MHI driver, MHI driver reads firmware from filesystem and boots it. Add
provision to read firmware files from ath11k driver and provide the amss.bin
firmware data and size to MHI using a pointer.

Currently enum ath11k_fw_features is empty, the patches adding features will
add the flags.

With AHB devices there's no amss.bin or m3.bin, so no changes in how AHB
firmware files are used. But AHB devices can use future additions to the meta
data, for example in enum ath11k_fw_features.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.9

Co-developed-by: P Praneesh <quic_ppranees@quicinc.com>
Signed-off-by: P Praneesh <quic_ppranees@quicinc.com>
Signed-off-by: Anilkumar Kolli <quic_akolli@quicinc.com>
Co-developed-by: Kalle Valo <quic_kvalo@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230727100430.3603551-4-kvalo@kernel.org