virt: acrn: Replace obsolete memalign() with posix_memalign()

memalign() is obsolete according to its manpage.

Replace memalign() with posix_memalign() and remove malloc.h include
that was there for memalign().

As a pointer is passed into posix_memalign(), initialize *p to NULL
to silence a warning about the function's return value being used as
uninitialized (which is not valid anyway because the error is properly
checked before p is returned).
Signed-off-by: Deming Wang <wangdeming@inspur.com>
Link: https://lore.kernel.org/r/20230412073041.2168-1-wangdeming@inspur.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

samples/acrn/vm-sample.c

@@ -13,7 +13,6 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
-#include <malloc.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <signal.h>
@@ -54,8 +53,8 @@ int main(int argc, char **argv)
 	argc = argc;
 	argv = argv;
 
-	guest_memory = memalign(4096, GUEST_MEMORY_SIZE);
-	if (!guest_memory) {
+	ret = posix_memalign(&guest_memory, 4096, GUEST_MEMORY_SIZE);
+	if (ret < 0) {
 		printf("No enough memory!\n");
 		return -1;
 	}