drm/xe/xe_sysctrl: Drop redundant endian conversions in mailbox header macros

drm/xe/xe_sysctrl: Drop redundant endian conversions in mailbox header macros

Remove unnecessary le32_to_cpu() conversions from XE_SYSCTRL_APP_HDR_*
macros.

Fixes: 37ace5254a2b ("drm/xe/xe_sysctrl: Add ABI and mailbox interface headers")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604010228.Z20DhK4g-lkp@intel.com/
Signed-off-by: Anoop Vijay <anoop.c.vijay@intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Link: https://patch.msgid.link/20260408110759.1407342-2-anoop.c.vijay@intel.com