docs/manual/pkg-cmake.txt: fix _INSTALL_STAGING_OPTS/_INSTALL_TARGET_OPTS description

Since commit dfcc18f84b0d90b0ed5937bac3c4b12aba086cd5 cmake-package
_INSTALL_STAGING_OPTS/_INSTALL_TARGET_OPTS use 'install/fast'
instead of 'install', adjust documentation accordingly.

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
1 file changed