This commit renames the REG_BUS_FEEDBEAD to REG_BUS_TEST_RO
(Read-Only) which is the name used in the specification, section 4.2.3
Table 6.
It also adds a constant named REG_BUS_TEST_RW (Read-Write) to represent
the dummy register which the host can use to write data and read back
to check that the gSPI interface is working properly.
This commit add comments about what CLM stands for.
The motivation of this is that I think it helps understanding the code
for users who are new to the codebase (like me).
For some reason I got strange events on channel 1 (ASYNCEVENT_HEADER):
0.647329 WARN unexpected ehternet type 0x0508, expected Qualcom ether type 0x886c
This patch improves the validation of BCD WHD events to minimize the
risk for panic.
