fbdev/core: Avoid uninitialized read in aperture_remove_conflicting_pci_device()

Return on error directly from the BAR-iterating loop instead of
break+return.

This is actually a cosmetic fix, since it would be highly unusual to
have this called for a PCI device without any memory BARs.

Fixes: 9d69ef18 ("fbdev/core: Remove remove_conflicting_pci_framebuffers()")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/e75323732bedc46d613d72ecb40f97e3bc75eea8.1666829073.git.mirq-linux@rere.qmqm.pl