hal: microchip: sam: add the three SPI aliases the D5x/E5x pack lacks

[TheArkadiuszGrzelka]

Moving the SPI driver onto the generic SERCOM_SPI_ names needs three aliases the D5x/E5x pack never defined, and this is the one family whose Kconfig compiles the CTRLC line at all.

Three names missing from forty

sercom_samd5xe5x.h maps the generic SERCOM_SPI_ names onto this pack's
SERCOM_SPIM_ ones, some forty of them, and three are absent:
CTRLA_SWRST, SYNCBUSY_SWRST and CTRLC_ICSPACE.

Nothing noticed, because spi_mchp_sercom_g1.c reached past the mapping and
used the SPIM spelling directly in exactly those four places. That direct
use is what stops the driver building on PIC32CM SG/GC, which has one SPI
block and no SPIM prefix at all.

The family where the third name matters

SPI_MCHP_INTER_CHARACTER_SPACE is depends on SOC_FAMILY_MICROCHIP_SAM_D5X_E5X, so the CTRLC write is compiled here and
nowhere else. On PIC32CM JH the same three-name gap exists for the two
SWRST names only: that pack has no SPIM CTRLC register at all, and the
Kconfig can never select it, so aliasing CTRLC_ICSPACE there would be a
definition pointing at a name that does not exist.

sam_e54_xpro is the in-tree board that carries this pack and a
microchip,sercom-g1-spi node.

Scope

Six lines in one header, all of the same one-line form as the forty already
in it. Nothing that compiles today changes meaning: on this pack each new
generic name resolves to the SPIM definition the driver used before.

Testing

samples/hello_world on sam_e54_xpro with CONFIG_SPI=y and
CONFIG_SPI_MCHP_INTER_CHARACTER_SPACE=1, with the Zephyr generic-names
change in the tree. spi_mchp_sercom_g1.c.obj is built, and the generated
autoconf.h carries CONFIG_SPI_MCHP_INTER_CHARACTER_SPACE 1, so the
CTRLC line inside the #ifdef is compiled rather than skipped - which is
the only way this pack's third alias gets exercised at all.

No D5x/E5x board is on this bench, so L3 is UNVERIFIED.

Verification

Built in the project's dev container, whose west workspace applies this
change as a module patch. This is one of the consumer-side pairs of
zephyrproject-rtos/zephyr's spi-mchp-sercom-g1-generic-names; the other
is sercom-jh-spi-aliases, and all three have to land in the same window.