first_stage_console: Address compiler warning

Re-order the fields in the declaration to address the following

  ISO C++ requires field designators to be specified in declaration order;
  field 'sigaction::(anonymous union at bionic/libc/include/bits/signal_types.h:76:20)'
  will be initialized after field 'sa_flags' [-Wreorder-init-list]

Test: TH
Change-Id: I3f1d4739f1677aad50d4f07361aa264da43bdd13