staging: r8822be: fix memory leak of eeprom_map on error exit return

A memory leak of eeprom_map occurs if the call to halmac_eeprom_parser_88xx
fails. Fix this by kfree'ing it before returning.

Detected by CoverityScan, CID#1454569 ("Resource leak")
Fixes: 938a0447 ("staging: r8822be: Add code for halmac sub-driver")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>