net/ipxe: update g20230719 (c1834f32) to g20230822 (9e99a55b317f5da6)

• this change applies 9e99a55b317f5da6 and c30b71ee9cc2dc2a from upstream
• [virtio] Fix implementation of vpm_ioread32()
  
  The current implementation of vpm_ioread32() erroneously reads only 16 bits of data, which fails when used with the (stricter) virtio device emulation in VirtualBox.
  
  Fix by using the correct readl()/inl() I/O wrappers.
• [image] Check delimiters when parsing command-line key-value arguments
  
  The Linux kernel bzImage image format and the CPIO archive constructor will parse the image command line for certain arguments of the form "key=value". This parsing is currently implemented using strstr() in a way that can cause a false positive suffix match. For example, a command line containing "highmem=<n>" would erroneously be treated as containing a value for "mem=<n>".
  
  Fix by centralising the logic used for parsing such arguments, and including a check that the argument immediately follows a whitespace delimiter (or is at the start of the string).

PR: 272483
Reported by: mikael@