RAS_MAX_RECORD_NUM may mean the maximum record
number, as in the maximum house number on your
street, or it may mean the maximum number of
records, as in the count of records, which is also
a number. To make this distinction whether the
number is ordinal (index) or cardinal (count),
rename this macro to RAS_MAX_RECORD_COUNT.

This makes it easy to understand what it refers
to, especially when we compute quantities such as,
how many records do we have left in the table,
especially when there are so many other numbers,
quantities and numerical macros around.

Also rename the long,
amdgpu_ras_eeprom_get_record_max_length() to the
more succinct and clear,
amdgpu_ras_eeprom_max_record_count().

When computing the threshold, which also deals
with counts, i.e. "how many", use cardinal
"max_eeprom_records_count", than the quantitative
"max_eeprom_records_len".

Simplify the logic here and there, as well.

Cc: Guchun Chen <guchun.chen@amd.com>
Cc: John Clements <john.clements@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>