Correct module naming.
* video/efi_uga.c (GRUB_MOD_INIT(efi_fb)): Renamed from this ...
(GRUB_MOD_INIT(efi_uga)): ... to this
(GRUB_MOD_FINI(efi_fb)): Renamed from this ...
(GRUB_MOD_FINI(efi_uga)): ... to this
* video/efi_gop.c (GRUB_MOD_INIT(efi_fb)): Renamed from this ...
(GRUB_MOD_INIT(efi_gop)): ... to this
(GRUB_MOD_FINI(efi_fb)): Renamed from this ...
(GRUB_MOD_FINI(efi_gop)): ... to this