ati_radeon: return with error when emulator fails

Console was being switched to video even if emulator fails and
causing this hang:

               Scanning PCI bus 04
        04  00  1095  3132  0104  00
    PCIE3 on bus 03 - 04
Video: ATI Radeon video card (1002, 5b60) found @(2:0:0)
videoboot: Booting PCI video card bus 2, function 0, device 0
videoboot: Video ROM failed to map!
640x480x8 31kHz 59Hz
radeonfb: FIFO Timeout !

Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Tested-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/bios_emulator/atibios.c b/drivers/bios_emulator/atibios.c
index 5f9bd10..2881449 100644
--- a/drivers/bios_emulator/atibios.c
+++ b/drivers/bios_emulator/atibios.c
@@ -315,7 +315,8 @@
 	BE_init(0, 65536, VGAInfo, 0);
 
 	/*Post all the display controller BIOS'es*/
-	PCI_postController(pcidev, VGAInfo);
+	if (!PCI_postController(pcidev, VGAInfo))
+		return false;
 
 	/*Cleanup and exit the emulator if requested. If the BIOS emulator
 	is needed after booting the card, we will not call BE_exit and