x86/microcode/intel: Simplify generic_load_microcode_early()

* remove state variable and out label
* get rid of completely unused mc_size
* shorten variable names
* get rid of local variables
* don't do assignments in local var declarations for less cluttered code
* finally rename it to the shorter and perfectly fine load_microcode_early()

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>