libpayload/libpci: Clean up pci_alloc()

Clean up pci_alloc() and return pointer to allocated memory directly.

Change-Id: Ib2ee8dbfaabbf7a824b4fd75ad7c779393af2900
Signed-off-by: Felix Singer <felix.singer@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46345
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>

payloads/libpayload/libpci/libpci.c

@@ -72,8 +72,7 @@ int pci_write_long(struct pci_dev *dev, int pos, u32 data)
 
 struct pci_access *pci_alloc(void)
 {
-	struct pci_access *pacc = malloc(sizeof(*pacc));
-	return pacc;
+	return malloc(sizeof(struct pci_access));
 }
 
 void pci_init(struct pci_access *pacc)