MIPS: pic32mzda: Fix linker error for pic32_get_pbclk()

MIPS: pic32mzda: Fix linker error for pic32_get_pbclk()

Early clock API pic32_get_pbclk() is defined in early_clk.c and used by
time.c and early_console.c. When CONFIG_EARLY_PRINTK isn't set,
early_clk.c isn't compiled and time.c fails to link.

Fix it by compiling early_clk.c always. Also sort files in alphabetical
order.

Fixes: 6e4ad1b41360 ("MIPS: pic32mzda: fix getting timer clock rate.")
Reported-by: Harvey Hunt <harvey.hunt@imgtec.com>
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Harvey Hunt <harvey.hunt@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Joshua Henderson <digitalpeer@digitalpeer.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.7.x-
Patchwork: https://patchwork.linux-mips.org/patch/13383/
Signed-off-by: James Hogan <james.hogan@imgtec.com>