powerpc/kexec/core: use big-endian types for crash variables

powerpc/kexec/core: use big-endian types for crash variables

Use explicit word-sized big-endian types for kexec and crash related
variables. This makes the endianness unambiguous and avoids type
mismatches that trigger sparse warnings.

The change addresses sparse warnings like below (seen on both 32-bit
and 64-bit builds):

CHECK   ../arch/powerpc/kexec/core.c
sparse:    expected unsigned int static [addressable] [toplevel] [usertype] crashk_base
sparse:    got restricted __be32 [usertype]
sparse: warning: incorrect type in assignment (different base types)
sparse:    expected unsigned int static [addressable] [toplevel] [usertype] crashk_size
sparse:    got restricted __be32 [usertype]
sparse: warning: incorrect type in assignment (different base types)
sparse:    expected unsigned long long static [addressable] [toplevel] mem_limit
sparse:    got restricted __be32 [usertype]
sparse: warning: incorrect type in assignment (different base types)
sparse:    expected unsigned int static [addressable] [toplevel] [usertype] kernel_end
sparse:    got restricted __be32 [usertype]

No functional change intended.

Fixes: ea961a828fe7 ("powerpc: Fix endian issues in kexec and crash dump code")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512221405.VHPKPjnp-lkp@intel.com/
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20251224151257.28672-1-sourabhjain@linux.ibm.com