loader: Do not force comconsole for arm and arm64

This makes GOP not probed on some situation (AMD Card on PCIe slot
with EDK2 as we have a SERIAL_IO_PROTOCOL compatible uart).

Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D32992
Sponsored by: Beckhoff Automation GmbH & Co. KG

(cherry picked from commit 123b5b8)

stand/efi/loader/main.c

@@ -923,7 +923,7 @@ main(int argc, CHAR16 *argv[])
 	 */
 	setenv("console", "efi", 1);
 	uhowto = parse_uefi_con_out();
-#if defined(__aarch64__) || defined(__arm__) || defined(__riscv)
+#if defined(__riscv)
 	if ((uhowto & RB_SERIAL) != 0)
 		setenv("console", "comconsole", 1);
 #endif