wireless: rtlwifi: Replace variable with a break

This patch removes the variable continual, and change the while loop
to break when efuse_data == 0xFF.

Tested by compilation only.

CC: Joe Perches <joe@perches.com>
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>