kernel security and bug fix update

[kernel-2.4.21-57.0.0.0.1.EL]

• add directio support for qla drivers (herb) [ora 6346849]
• support PT Quad card [ora 5751043]
• [ora 5088963]: io to nfs partition hangs
• add entropy for bnx2 nic [ora 5931647]
• avoid large allocation-fragmentation in MTU (zab)
• fix clear highpage (wli)
  [kernel-2.4.21-57.EL]
• Update: Fix race condition in dnotify() (Al Viro) [439755 443436] {CVE-2008-1375 CVE-2008-1669}
  [kernel-2.4.21-56.EL]
• Fix race condition in dnotify() (Al Viro) [439755] {CVE-2008-1375}
• Fix machine check error on Clovertown G0 (Geoff Gustafson) [430924]
• Fix unaligned handler for FP instructions (Don Howard) [430919]
  [kernel-2.4.21-55.EL]
• Fix race condition in sys_mincore() (Don Howard) [247595] {CVE-2006-4814}
• Fix panic with AIO writes to pipes (Josef Bacik) [311621] {CVE-2007-5001}
• Fix error with coredump ownership (Don Howard) [396961] {CVE-2007-6206}
• Fix potential buffer overrun issue in isdn_ioctl (Don Howad) [425141] {CVE-2007-6151}
• Fix potential DoS with mremap (Don Howard) [428967] {CVE-2008-0007}
• Clear df flag for signal handlers (Don Howard) [437313] {CVE-2008-1367}
  [kernel-2.4.21-54.EL]
• Fix hang at unmount with many unused dentries (Josef Bacik) [413731]