ARM: imx: bootaux: Fix LTO -Wlto-type-mismatch

Commit 56c2dbdabab5 ("imx: bootaux: cleanup code") introduces the
following LTO related warning:

"
arch/arm/mach-imx/imx_bootaux.c:24:31: warning: type of ‘hostmap’ does not match original declaration [-Wlto-type-mismatch]
   24 | const __weak struct rproc_att hostmap[] = { };
      |                               ^
arch/arm/mach-imx/imx8m/soc.c:1590:24: note: array types have different bounds
 1590 | const struct rproc_att hostmap[] = {
      |                        ^
arch/arm/mach-imx/imx8m/soc.c:1590:24: note: ‘hostmap’ was previously declared here
../aarch64-linux-gnu/bin/ld: warning: u-boot has a LOAD segment with RWX permissions
"

This is because the weak empty array of structures "hostmap" is eventually
replaced by non-empty array of structures with different number of elements.
Fix this by avoiding weak variable size array, instead use a weak function
which returns single pointer to the array.

Fixes: 56c2dbdabab5 ("imx: bootaux: cleanup code")
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/imx8m/soc.c b/arch/arm/mach-imx/imx8m/soc.c
index 8050406..90a59bd 100644
--- a/arch/arm/mach-imx/imx8m/soc.c
+++ b/arch/arm/mach-imx/imx8m/soc.c
@@ -1610,4 +1610,9 @@
 	{ 0x40000000, 0x40000000, 0x80000000 },
 	{ /* sentinel */ }
 };
+
+const struct rproc_att *imx_bootaux_get_hostmap(void)
+{
+	return hostmap;
+}
 #endif