Hi everybody.

This patch fixes the

     Ok, booting the kernel.         [hangs]

problem with BIOSes that report E820 memory maps with zero-size entries.
Among the mainboards affected are

     EPOX 4G4A+ (presumably)
     EPOX 4BEA[-R]
     Chaintech 9EJL  .

In the past (kernels up to 2.4.20), these mainboards could only boot Linux
with explicit 'mem=' boot parameters.

Up to 2.4.20, a zero-size E820 memory region (eg 0xa0000 - 0xa0000)
reported by the BIOS causes 'sanitize_e820_map' to take the end of this
region as the start of another region, producing two overlapping regions
extending to the end of addressable memory. If the zero-size region is of
a higher type than 'usable RAM' (eg 'reserved'), this causes all memory
above the zero-size region to be marked unusable (leaving 640k as of the
above example -- the kernel fails to start at all).

The patch adds code to remove empty entries before sorting regions. It
was generated for a 2.4.20 kernel.

Best regards,
Alex

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