Updated OpenWrt builds for 21.02.0. Non-OpenWrt users need not upgrade.
- Re-added arm_arm1176jzf-s_vfp, arm_arm926ej-s, arm_mpcore, arm_xscale due to previously missing
arm_use_thumb=false
in build. - Re-added arm_cortex-a5_vfpv4, missing in 19.07.8 but back in 21.02.0.
- Added arm_cortex-a7 (mediatek/mt7629), new in 21.02.0.
- Removed arm_cortex-a8_neon (samsung/s5pv210), removed in 21.02.0.