arm: mach-k3: Enable dcache in SPL

Add support for enabling dcache already in SPL. It accelerates the boot
and resolves the risk to run into unaligned 64-bit accesses.

Based on original patch by Lokesh Vulta.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Lokesh Vutla <lokeshvutla@ti.com>
diff --git a/arch/arm/mach-k3/common.h b/arch/arm/mach-k3/common.h
index 57682e1..94cdcb5 100644
--- a/arch/arm/mach-k3/common.h
+++ b/arch/arm/mach-k3/common.h
@@ -27,3 +27,4 @@
 void start_non_linux_remote_cores(void);
 int load_firmware(char *name_fw, char *name_loadaddr, u32 *loadaddr);
 void k3_sysfw_print_ver(void);
+void spl_enable_dcache(void);