Fix dependencies for parallel make and others

Fix dependencies for parallel make and others

Since the keys .c files are included by reglib.c, it's not the final
output to depend on them but rather reglib.o.

This not only fixes proper regeneration of reglib.o when the pem files
are changed, but also allows proper parallel make of the package.

Signed-off-by: Diego E. 'Flameeyes' Pettenò <flameeyes@gmail.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>