net/ipxe: update g20230822 (9e99a55b) to g20240403 (59f27d69)

• delete 'files/patch-src_arch_x86_include_librm.h' as it's now landed in upstream code; https://github.com/ipxe/ipxe/pull/1036
• other upstream changes include, but are not limited to:
  • [bnxt] Add support for BCM957608;
  • [build] Fix building on older versions of gcc;
  • [build] Fix building with newer binutils;
  • [crypto] Add X25519 key exchange algorithm;
  • [crypto] Add implementation of MS-CHAPv2 authentication (RFC2759);
  • [efi] Update to current EDK2 headers;
  • [intel] Add PCI ID for I219-LM (23), OK on FUJITSU LIFEBOOK U7413;
  • [libc] Replace linker_assert() with build_assert();
  • [librm] Use explicit operand size when pushing a label address;
  • [tls] Add ECDHE cipher suites;
  • [tls] Add support for Ephemeral Elliptic Curve Diffie-Hellman K.E;
  • [ucode] Add support for updating x86 microcode;