[make] Remove .hex file from all target
[make] Remove .hex file from all target

This fileformat does not support large offsets, and fail to build if
the kernel base is at a high address on 64 bit systems.

Change-Id: I4e2cb58f46c62fded0de485c982dfdc5b6f3622f

grub4android/lk,littlekernel/lk,skabet/lk,srodrig1/lk,grub4android/lk,grub4android/lk,ErikCorryGoogle/lk,srodrig1/lk,ErikCorryGoogle/lk,GCrean/lk,grub4android/lk,srodrig1/lk,GCrean/lk,nvll/lk,skabet/lk,littlekernel/lk,littlekernel/lk,GCrean/lk,grub4android/lk,travisg/lk,srodrig1/lk,skabet/lk,skabet/lk,ErikCorryGoogle/lk,minglun-tsai/lk,littlekernel/lk,srodrig1/lk,GCrean/lk,minglun-tsai/lk,nvll/lk,minglun-tsai/lk,sndnvaps/lk,sndnvaps/lk,nvll/lk,GCrean/lk,hollanderic/lkstuff,nvll/lk,ErikCorryGoogle/lk,travisg/lk,nvll/lk,sndnvaps/lk,travisg/lk,skabet/lk,hollanderic/lkstuff,travisg/lk,hollanderic/lkstuff,sndnvaps/lk,sndnvaps/lk,hollanderic/lkstuff,minglun-tsai/lk