core/linux-rpi: slim down cmdline.txt

Removed the following parameters:
1. selinux=0
2. plymouth.enable=0
3. smsc95xx.turbo_mode=N
4. dwc_otg.lpm_enable=0
5. kgdboc=serial0,115200

Notes:
1. force not loading SELinux infrastructure which we currently do not supply
2. force disabling of plymouth which I think we do not supply
3. avoided network issues under heavy load circa 2012 likely no longer needed
4. turned off link power management which may have prevented issues with shitty
   drivers in older kernels likely not an issue on a modern kernel tree
5. enabled debugging over the serial console which is unnecessary for most
   user... advanced users will likely be savvy enough with cmdline.txt to
   edit it to match their needs

core/linux-rpi/PKGBUILD

@@ -28,7 +28,7 @@ source=("linux-$pkgver-${_commit:0:10}.tar.gz::https://github.com/raspberrypi/li
         90-linux.hook
 )
 md5sums=('decc95d4231f214895ba5cf61d8c2233'
-         '31c02f4518d46deb5f0c2ad1f8b083cd'
+         '6f2eb280d7f10c1926ae6ebe54fbcc96'
          'f66a7ea3feb708d398ef57e4da4815e9'
          '86d4a35722b5410e3b29fc92dae15d4b'
          '0a5f16bfec6ad982a2f6782724cca8ba'

core/linux-rpi/cmdline.txt

@@ -1 +1 @@
-root=/dev/mmcblk0p2 rw rootwait console=serial0,115200 console=tty1 selinux=0 plymouth.enable=0 smsc95xx.turbo_mode=N dwc_otg.lpm_enable=0 kgdboc=serial0,115200
+root=/dev/mmcblk0p2 rw rootwait console=serial0,115200 console=tty1 rootfstype=ext4 fsck.repair=yes