efi: arm: Avoid allocating page tables when running under EFI

The previous bootloader has already set up the page tables, so don't try
to do it again.

This fixes a crash in QEMU when booting from EDK2

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/arm/lib/cache.c

@@ -6,6 +6,7 @@
 
 #include <config.h>
 #include <cpu_func.h>
+#include <init.h>
 #include <log.h>
 #include <malloc.h>
 #include <asm/cache.h>
@@ -138,6 +139,8 @@ int arch_reserve_mmu(void)
 
 __weak int arm_reserve_mmu(void)
 {
+	if (!ll_boot_init())
+		return 0;
 #if !(CONFIG_IS_ENABLED(SYS_ICACHE_OFF) && CONFIG_IS_ENABLED(SYS_DCACHE_OFF))
 	/* reserve TLB table */
 	gd->arch.tlb_size = PGTABLE_SIZE;