qemu: Convert KVMOPTS to PACKAGECONFIG
Move the KVMOPTS configuration checks and option setting to a
PACKAGECONFIG option.
This also changes the checking of KVM support on the host build machine
so that it is processed as a PACKAGECONFIG _remove for class-native
only. The darwin/mingw32 overrides are kept and applied as _remove
overrides.
(From OE-Core rev:
75a1dd39a63329e9b2d41d3a12ff58049248d2ff)
Signed-off-by: Nathan Rossi <nathan@nathanrossi.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>