Documentation: features: refresh feature list

Documentation: features: refresh feature list

Run the update script to document the recent feature additions
on riscv, mips and csky.

Fixes: c109f42450ec ("csky: Add kmemleak support")
Fixes: 8b3165e54566 ("MIPS: Enable GCOV")
Fixes: 1ddc96bd42da ("MIPS: kernel: Support extracting off-line stack traces from user-space with perf")
Fixes: 74784081aac8 ("riscv: Add uprobes supported")
Fixes: 829adda597fe ("riscv: Add KPROBES_ON_FTRACE supported")
Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Fixes: dcdc7a53a890 ("RISC-V: Implement ptrace regs and stack API")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210225142841.3385428-2-arnd@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>