x86/sgx: Fix minor documentation issues

The SGX documentation has a few repeated or one-off issues:

 * Remove capitalization from regular words in the middle of a sentence.
 * Remove punctuation found in the middle of a sentence.
 * Fix name of SGX daemon to consistently be ksgxd.
 * Fix typo of SGX instruction: ENIT -> EINIT

[ dhansen: tweaked subject and changelog ]

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lkml.kernel.org/r/ab99a87368eef69e3fb96f073368becff3eff874.1635529506.git.reinette.chatre@intel.com