disp: msm: compat: add kernel 7.2 backward-compatibility shims

[yashgupta2126]

Kernel 7.2 introduced several breaking API changes that prevent sde-dlkm from compiling. Add a new compat header
include/linux/msm_drm_compat.h that centralises all version-guarded shims, and include it at the affected call sites.

All shims are gated on LINUX_VERSION_CODE >= KERNEL_VERSION(7, 2, 0) so there is no functional change on kernel < 7.2.

Changes covered:

1. struct drm_atomic_state renamed to struct drm_atomic_commit. All associated APIs renamed accordingly: drm_atomic_state_init/get/put/alloc/clear drm_atomic_state_default_clear/default_release Fix: #define aliases mapping old names to new names. Include compat header in msm_drv.h so all TUs pick it up.

2. drm_atomic_private_obj_init() dropped its initial state argument. Fix: inline wrapper absorbs the removed argument without touching call sites.

3. drm_private_state_funcs gained atomic_create_state callback. Fix: dp_mst_drm.c adds the callback under a version guard.

4. thermal_of_cooling_device_register() gained a new u32 cdev_id argument as its 2nd parameter. Fix: inline wrapper accepts the old 4-arg form and forwards to the new 5-arg API with cdev_id=0 (preserving legacy behaviour). Inline is defined before the #define to avoid macro recursion. Include compat header in msm_cooling_device.c.

5. drm_panel_init() made static/unexported. sde-dlkm kzalloc-s a bare drm_panel and calls drm_panel_init(). Fix: inline __msm_drm_panel_init_compat() replicates the last exported body (INIT_LIST_HEAD list/followers, mutex_init, field assignments), shadowed by a #define at call sites.

6. qcom_clk_set_flags() and CLKFLAG_RETAIN_MEM/CLKFLAG_NORETAIN_MEM removed from <linux/clk/qcom.h>. The header still exists with a different API so the __has_include guard in sde_power_handle.c passes, but the symbol is no longer declared or exported. Fix: no-op stubs in compat header; the retain-mem hint is advisory only and safe to elide. Include compat header in sde_power_handle.c.