fscrypt: Drop obsolete recommendation to enable optimized POLYVAL

CONFIG_CRYPTO_POLYVAL_ARM64_CE and CONFIG_CRYPTO_POLYVAL_CLMUL_NI no
longer exist. The architecture-optimized POLYVAL code is now just
enabled automatically when HCTR2 support is enabled. Update the fscrypt
documentation accordingly.

Reviewed-by: Ard Biesheuvel <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Eric Biggers <[e-mail]>

Documentation/filesystems/fscrypt.rst

···
         - CONFIG_CRYPTO_HCTR2
     - Recommended:
         - arm64: CONFIG_CRYPTO_AES_ARM64_CE_BLK
-        - arm64: CONFIG_CRYPTO_POLYVAL_ARM64_CE
         - x86: CONFIG_CRYPTO_AES_NI_INTEL
-        - x86: CONFIG_CRYPTO_POLYVAL_CLMUL_NI
 
 - Adiantum
     - Mandatory: