ANDROID: gki_defconfig: Enable CONFIG_RANDOM_TRUST_CPU=y

Systems with a single early entropy source based on either CPU
instructions or a firmware interface are unable to initialise the crng
unless the CPU is "trusted". By default, the CPU is untrusted and so for
protected virtual machines this causes a significant boot delay as the
crng refuses to initialise solely from the TRNG hypercall:

  | [    0.000000][    T0] random: get_random_u64 called from kmem_cache_open+0x2c/0x390 with crng_init=0
  | ...
  | [    1.297022][  T211] EXT4-fs (dm-24): mounted filesystem without journal. Opts: (null)
  | [    3.362924][    C0] random: crng init done
  | [    3.363543][    C0] random: 7 urandom warning(s) missed due to ratelimiting

Since we trust the CPU and the firmware for many other things, such as
executing instructions and initialising the system, flip the default
around to trust CPU-backed entropy sources by default. This can be
disabled on the kernel command-line by passing "random.trust_cpu=off".

Bug: 220354122
Reported-by: Alan Stokes <alanstokes@google.com>
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Ie09b6253936823814d7bfe5092923f0ec825403a

arch/arm64/configs/gki_defconfig

@@ -396,6 +396,7 @@ CONFIG_HW_RANDOM=y
 # CONFIG_HW_RANDOM_CAVIUM is not set
 # CONFIG_DEVMEM is not set
 # CONFIG_DEVPORT is not set
+CONFIG_RANDOM_TRUST_CPU=y
 # CONFIG_I2C_COMPAT is not set
 # CONFIG_I2C_HELPER_AUTO is not set
 CONFIG_I3C=y

arch/x86/configs/gki_defconfig

@@ -359,6 +359,7 @@ CONFIG_HW_RANDOM=y
 # CONFIG_DEVMEM is not set
 # CONFIG_DEVPORT is not set
 CONFIG_HPET=y
+CONFIG_RANDOM_TRUST_CPU=y
 # CONFIG_I2C_COMPAT is not set
 # CONFIG_I2C_HELPER_AUTO is not set
 CONFIG_I3C=y