drivers: ieee802154: cc13xx_cc26xx: Allow both radios to coexist

Currently the 2.4G radio driver for CC1352 has few implementations which
prevents both the radios to be used in a single build, thus preventing
applications to have different builds to switch the RF bands even though
the hardware supports dual bands simultaneously.

The following updates are made:
 * Remove RF patches from stack.
 * Implement if_stop() to stop the interface and yield the interface.
 * Use RF_runCmd() instead of RF_runImmediateCmd() so that two RF handles
 can work simultaneously.

All the updates are similar to the more recent cc13xx subg driver which
implements all these recommended practices already.

Signed-off-by: Vaishnav Achath <vaishnav.a@ti.com>