efi: sysfb_efi: remove unnecessary <asm/efi.h> include

Nothing defined in the header is used by drivers/firmware/efi/sysfb_efi.c
but also, including it can lead to build errors when built on arches that
don't have an asm/efi.h header file.

This can happen for example if a driver that is built when COMPILE_TEST is
enabled selects the SYSFB symbol, e.g. on powerpc with allyesconfig:

drivers/firmware/efi/sysfb_efi.c:29:10: fatal error: asm/efi.h: No such file or directory
   29 | #include <asm/efi.h>
      |          ^~~~~~~~~~~
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/sysfb_efi.c

@@ -26,8 +26,6 @@
 #include <linux/sysfb.h>
 #include <video/vga.h>
 
-#include <asm/efi.h>
-
 enum {
 	OVERRIDE_NONE = 0x0,
 	OVERRIDE_BASE = 0x1,