pru-software-support: bump to latest version 5.7.0

Update to the latest version of the PRU software support [1].

There are minor changes to the license file mostly dates and versions --
notably pulling in several Linux kernel 5.4 header files in place of the
4.19 versions.  As there is no longer a dependency on the kernel types.h
  header, there's no longer a GPL-2.0 licensed component.

Also drop the useless comment that just repeats the URL.

[1] https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package

Signed-off-by: Ash Charles <ashcharles@gmail.com>
[yann.morin.1998@free.fr: drop the URL-as-comment]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/pru-software-support/pru-software-support.hash

@@ -1,3 +1,3 @@
 # Locally-calculated hash
-sha256  d6d1f76ab5a50dbdf1dff834b271f9d3ffa7424e4d9615e00713f3f81ed5787e  pru-software-support-package-v5.6.0.tar.gz
-sha256  a68530804624227e4f2e007eacb5c2d616695426082e895ee1e2d77d3833f5f7  PRU-Package-v6.0-Manifest.html
+sha256  57e47128dc5437c5a64d4ef94f419d9ea38e894c0c31ab10cad99c0da614b296  pru-software-support-package-v5.7.0.tar.gz
+sha256  62a2f56498cd1bac2d4ea6ea1c941affba1e4bb65bfdf2dcffd8e5079fa34399  PRU-Package-v6.1-Manifest.html

package/pru-software-support/pru-software-support.mk

@@ -4,12 +4,11 @@
 #
 ################################################################################
 
-PRU_SOFTWARE_SUPPORT_VERSION = 5.6.0
-# https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package/snapshot/pru-software-support-package-5.6.0.tar.gz
+PRU_SOFTWARE_SUPPORT_VERSION = 5.7.0
 PRU_SOFTWARE_SUPPORT_SITE = https://git.ti.com/cgit/pru-software-support-package/pru-software-support-package/snapshot
 PRU_SOFTWARE_SUPPORT_SOURCE = $(PRU_SOFTWARE_SUPPORT_NAME)-package-v$(PRU_SOFTWARE_SUPPORT_VERSION).tar.gz
-PRU_SOFTWARE_SUPPORT_LICENSE =  BSD-3-Clause, GPL-2.0, Public Domain
-PRU_SOFTWARE_SUPPORT_LICENSE_FILES = PRU-Package-v6.0-Manifest.html
+PRU_SOFTWARE_SUPPORT_LICENSE =  BSD-3-Clause, Public Domain
+PRU_SOFTWARE_SUPPORT_LICENSE_FILES = PRU-Package-v6.1-Manifest.html
 PRU_SOFTWARE_SUPPORT_DEPENDENCIES = host-ti-cgt-pru host-pru-software-support
 HOST_PRU_SOFTWARE_SUPPORT_DEPENDENCIES = host-ti-cgt-pru