mod/mhu3: Fix doorbell channel trigger interrupt
Created by: girishpathak
To trigger an interrupt on a doorbell channel corresponding PDBCW_ST bit of the PBX(postbox) is validated. If corresponding bit is unset then the code will raise the doorbell interrupt, otherwise it will return an error FWK_E_STATE. This validation check is incorrect and this change fixes this.
Change-Id: I84b19832b1d128176a2b77f2f5abc3c3cb1d92c0 Signed-off-by: Girish Pathak girish.pathak@arm.com