package/dhcp: security bump to version 4.4.2-P1

Fixes the following security issue:

- CVE-2021-25217: A buffer overrun in lease file parsing code can be used to
  exploit a common vulnerability shared by dhcpd and dhclient

For details, see the advisory:
https://kb.isc.org/docs/cve-2021-25217

Update the LICENSE hash for a change of copyright years.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/dhcp/dhcp.hash

@@ -1,4 +1,4 @@
-# Verified from https://ftp.isc.org/isc/dhcp/4.4.2/dhcp-4.4.2.tar.gz.sha256.asc
-sha256  1a7ccd64a16e5e68f7b5e0f527fd07240a2892ea53fe245620f4f5f607004521  dhcp-4.4.2.tar.gz
+# Verified from https://ftp.isc.org/isc/dhcp/4.4.2-P1/dhcp-4.4.2-P1.tar.gz.sha256.asc
+sha256  b05e04337539545a8faa0d6ac518defc61a07e5aec66a857f455e7f218c85a1a  dhcp-4.4.2-P1.tar.gz
 # Locally calculated
-sha256  89e7b0661134cc118bdcdeb87ff0493d544bc5723c9ca6616fa05f03539738af  LICENSE
+sha256  9961fce0d83a6229b9084cdadedfa723a53274c63af610c9adb61b607e0f5a76  LICENSE

package/dhcp/dhcp.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-DHCP_VERSION = 4.4.2
+DHCP_VERSION = 4.4.2-P1
 DHCP_SITE = http://ftp.isc.org/isc/dhcp/$(DHCP_VERSION)
 DHCP_INSTALL_STAGING = YES
 DHCP_LICENSE = MPL-2.0