rtlwifi: rtl8821ae: make array static const and remove redundant assignment

rtlwifi: rtl8821ae: make array static const and remove redundant assignment

The array channel_all can be make static const rather than populating
it on the stack, this makes the code smaller.  Also, variable place
is being initialized with a value that is never read, so this assignment
is redundant and can be removed.

Before:
   text	   data	    bss	    dec	    hex	filename
 118537	   9591	      0	 128128	  1f480	realtek/rtlwifi/rtl8821ae/phy.o

After:
   text	   data	    bss	    dec	    hex	filename
 118331	   9687	      0	 128018	  1f412	realtek/rtlwifi/rtl8821ae/phy.o

Saves 110 bytes, (gcc version 9.2.1, amd64)

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>