lib: decompress_bunzip2: fix 32-bit shift undefined behavior

lib: decompress_bunzip2: fix 32-bit shift undefined behavior

Fix undefined behavior caused by shifting a 32-bit integer by 32 bits
during decompression.  This prevents potential kernel decompression
failures or corruption when parsing malicious or malformed bzip2 archives.

Link: https://lkml.kernel.org/r/20260308165012.2872633-1-objecting@objecting.org
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>