When wlc_phy_txpwr_srom_read_lcnphy fails in wlc_phy_attach_lcnphy,
the allocated pi->u.pi_lcnphy is leaked, since struct brcms_phy will be
freed in the caller function.

Fix this by calling wlc_phy_detach_lcnphy in the error handler of
wlc_phy_txpwr_srom_read_lcnphy before returning.
Signed-off-by: Keita Suzuki <keitasuzuki.park@sslab.ics.keio.ac.jp>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200908121743.23108-1-keitasuzuki.park@sslab.ics.keio.ac.jp