README.md: Fix typo in command-line example
README.md: Fix typo in command-line example

Chosen C library is set with TCLIBC, not LIBC.

Signed-off-by: Jacob Kroon <ddbd01327a7e4b334cb43711ea23bf170bbcce7a@mikrodidakt.se>
Signed-off-by: Khem Raj <729d64b6f67515e258459a5f6d20ec88b2caf8df@gmail.com>

kraj/meta-musl,armcc/meta-musl